sparc32: introduce asm-generic/io.h

Use asm-generic/io.h definitions where applicable.
The inxx() and outxx() methods whcih was duplicated in pcic.c +
leon_pci.c are replaced by a set of static inlins from asm-generic/io.h

iomap.c is replaced by the generic versions, but are still
present to support sparc64.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Daniel Hellstrom <daniel@gaisler.com>
Signed-off-by: David S. Miller <davem@davemloft.net>