ARM: shmobile: fix shmobile_smp_apmu_suspend_init build failure for !SUSPEND

Patch d6d757c9

 ("ARM: shmobile: APMU: Add Core-Standby-state for
Suspend to RAM") added both an inline wrapper for shmobile_smp_apmu_suspend_init
and an empty function in arch/arm/mach-shmobile/platsmp-apmu.c. We get a
build failure when both are present, so this patch removes the one in the .c
file and keeps the inline version.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>