ARM: shmobile: mark shmobile_init_late as __init

Patch 35f2b0bd "ARM: shmobile: Move definition of shmobile_init_late()
to header" moved the definition of the shmobile_init_late function, but
dropped the __init annotation, which is now causing warnings because
the function calls shmobile_suspend_init, which is also marked init.

Without this patch, building kota2_defconfig results in:

WARNING: vmlinux.o(.text+0xb7c8): Section mismatch in reference from the function shmobile_init_late() to the function .init.text:shmobile_suspend_init()
The function shmobile_init_late() references
the function __init shmobile_suspend_init().
This is often because shmobile_init_late lacks a __init
annotation or the annotation of shmobile_suspend_init is wrong.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Magnus Damm <damm@opensource.se>
Cc: Simon Horman <horms@verge.net.au>