lowmemorykiller: Add Android-style oom-killer

Signed-off-by: Andrei F <luxneb@gmail.com>
Signed-off-by: Grarak <williye97@gmail.com>

Conflicts:
	arch/arm/mach-exynos/Kconfig
	drivers/staging/android/lowmemorykiller.c

Conflicts:
	arch/arm/mach-omap2/Kconfig
	drivers/staging/android/lowmemorykiller.c