alpha: unbreak percpu again

alpha: unbreak percpu again

Commit 09c0060fdb5a89de3c7351c212a528738ba1a979 ("FRV: Fix the section
attribute on UP DECLARE_PER_CPU()") cleaned up DECLARE/DEFINE_PER_CPU()
macros and in the process made alpha percpu.h include
include/asm-generic/percpu.h which breaks compilation due to duplicate
definitions.

Remove inclusion of generic asm helper file and define whatever necessary
in alpha header proper.

In the longer term, percpu definitions will be unified and all these
little subtlties will be removed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: David Howells <dhowells@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>