logger: Add sysfs interface to Enable / Disable Android Logger

- switching done via /sys/kernel/logger_mode interface
default is 0 (off)
Credits to AndiP

Change-Id: I7bf979dadd0ac7155e8a939a8693eef858bfb873
Async I/O latency to a ssd greatly increased, 34% gain (Creds: kleikamp)

Change-Id: I4a2f5d33db55052103d5dfc21719565197f725f8
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 "logger: Add sysfs interface to Enable / Disable Android Logger" into android-4.4
Merge "Async I/O latency to a ssd greatly increased, 34% gain (Creds: kleikamp)" into android-4.4
Merge "Optimized ARM RWSEM algorithm" into android-4.4