[PATCH] Shut up warnings in ipc/shm.c

Fix two warnings in ipc/shm.c

ipc/shm.c:122: warning: statement with no effect
ipc/shm.c:560: warning: statement with no effect

by converting the macros to empty inline functions.  For safety, let's do
all three.  This also has the advantage that typechecking gets performed
even without CONFIG_SHMEM enabled.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>