logger: Add sysfs interface to Enable / Disable Android Logger
- switching done via /sys/kernel/logger_mode interface
default is 0 (off)
Credits to AndiP
Picked from Wanam kernel GS4 :D
Makefile: adjust flags to be more like r19
-added back neon-vfpv4 instead of straight neon
-added stuff back to KBUILD_CFLAGS