arch/sh/include/asm/io.h: provide prototypes for PCI I/O mapping in asm/io.h

arch/sh/include/asm/io.h: provide prototypes for PCI I/O mapping in asm/io.h

Most architectures provide prototypes for the PCI I/O mapping operations
when asm/io.h is included but SH doesn't currently do that, leading to
for example warnings in sound/pci/hda/patch_ca0132.c when pci_iomap() is
used on current -next.  Make SH more consistent with other architectures
by including asm-generic/pci_iomap.h in asm/io.h.

Link: http://lkml.kernel.org/r/20181106175142.27988-1-broonie@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Reported-by: kbuild test robot <lkp@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>