arch/unicore32/kernel/ksyms.c: remove several undefined exported symbols

arch/unicore32/kernel/ksyms.c: remove several undefined exported symbols

For 'csum_partial_copy_nocheck()', it has default definition in
'asm-generic'.

For '__raw_reads?()' and '__raw_writes?()' are used by the drivers
which no relationship with allmodconfig for unicode32, the related
modules are:

  drivers/mmc/host/omap.c
  drivers/mtd/nand/atmel_nand.c
  drivers/mtd/nand/pxa3xx_nand.c
  drivers/usb/gadget/at91_udc.c

Others are only within some architectures (not kernel wide).

The related error with allmodconfig for unicode32:

    CC      arch/unicore32/kernel/ksyms.o
  arch/unicore32/kernel/ksyms.c:29: error: ._backtrace. undeclared here (not in a function)
  arch/unicore32/kernel/ksyms.c:29: error: type defaults to .nt. in declaration of ._backtrace.
  arch/unicore32/kernel/ksyms.c:38: error: .sum_partial_copy_nocheck. undeclared here (not in a function)
  arch/unicore32/kernel/ksyms.c:38: error: type defaults to .nt. in declaration of .sum_partial_copy_nocheck.
  arch/unicore32/kernel/ksyms.c:39: error: ._csum_ipv6_magic. undeclared here (not in a function)
  arch/unicore32/kernel/ksyms.c:39: error: type defaults to .nt. in declaration of ._csum_ipv6_magic.
  arch/unicore32/kernel/ksyms.c:43: error: ._raw_readsb. undeclared here (not in a function)
  arch/unicore32/kernel/ksyms.c:43: error: type defaults to .nt. in declaration of ._raw_readsb.
  arch/unicore32/kernel/ksyms.c:46: error: ._raw_readsw. undeclared here (not in a function)
  arch/unicore32/kernel/ksyms.c:46: error: type defaults to .nt. in declaration of ._raw_readsw.
  arch/unicore32/kernel/ksyms.c:49: error: ._raw_readsl. undeclared here (not in a function)
  arch/unicore32/kernel/ksyms.c:49: error: type defaults to .nt. in declaration of ._raw_readsl.
  arch/unicore32/kernel/ksyms.c:52: error: ._raw_writesb. undeclared here (not in a function)
  arch/unicore32/kernel/ksyms.c:52: error: type defaults to .nt. in declaration of ._raw_writesb.
  arch/unicore32/kernel/ksyms.c:55: error: ._raw_writesw. undeclared here (not in a function)
  arch/unicore32/kernel/ksyms.c:55: error: type defaults to .nt. in declaration of ._raw_writesw.
  arch/unicore32/kernel/ksyms.c:58: error: ._raw_writesl. undeclared here (not in a function)
  arch/unicore32/kernel/ksyms.c:58: error: type defaults to .nt. in declaration of ._raw_writesl.
  arch/unicore32/kernel/ksyms.c:79: error: ._get_user_1. undeclared here (not in a function)
  arch/unicore32/kernel/ksyms.c:79: error: type defaults to .nt. in declaration of ._get_user_1.
  arch/unicore32/kernel/ksyms.c:80: error: ._get_user_2. undeclared here (not in a function)
  arch/unicore32/kernel/ksyms.c:80: error: type defaults to .nt. in declaration of ._get_user_2.
  arch/unicore32/kernel/ksyms.c:81: error: ._get_user_4. undeclared here (not in a function)
  arch/unicore32/kernel/ksyms.c:81: error: type defaults to .nt. in declaration of ._get_user_4.
  arch/unicore32/kernel/ksyms.c:83: error: ._put_user_1. undeclared here (not in a function)
  arch/unicore32/kernel/ksyms.c:83: error: type defaults to .nt. in declaration of ._put_user_1.
  arch/unicore32/kernel/ksyms.c:84: error: ._put_user_2. undeclared here (not in a function)
  arch/unicore32/kernel/ksyms.c:84: error: type defaults to .nt. in declaration of ._put_user_2.
  arch/unicore32/kernel/ksyms.c:85: error: ._put_user_4. undeclared here (not in a function)
  arch/unicore32/kernel/ksyms.c:85: error: type defaults to .nt. in declaration of ._put_user_4.
  arch/unicore32/kernel/ksyms.c:86: error: ._put_user_8. undeclared here (not in a function)
  arch/unicore32/kernel/ksyms.c:86: error: type defaults to .nt. in declaration of ._put_user_8.

Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Acked-by: Xuetao Guan <gxt@mprc.pku.edu.cn>
Signed-off-by: Xuetao Guan <gxt@mprc.pku.edu.cn>