Optimized ARM RWSEM algorithm

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

Change-Id: I0e836157618a9757b5fe8ff1c799524b2dfda83b
Signed-off-by: Ashwin Chaugule <ashwinc@codeaurora.org>
Merge "Optimized ARM RWSEM algorithm" into next