Optimized ARM RWSEM algorithm

RWSEM implementation for ARM using atomic functions.
Heavily based on arch/sh/include/asm/rwsem.h

Signed-off-by: Ashwin Chaugule <ashwinc@codeaurora.org>
arch/arm/Kconfig: enable unaligned capability for ARM

Signed-off-by: faux123 <reioux@gmail.com>
drivers/media/video/msm/msm: fix compilation warning

Signed-off-by: Paul Reioux <reioux@gmail.com>