msm: io: Fix section mismatch warnings

WARNING: vmlinux.o(.text+0x15788): Section mismatch in reference
from the function msm_map_io() to the function
.init.text:iotable_init()
The function msm_map_io() references
the function __init iotable_init().
This is often because msm_map_io lacks a __init
annotation or the annotation of iotable_init is wrong.

Change-Id: Iff5c48cdfe9fc2ada46566a44803765ed2e6a80b
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>