drivers/staging/android/lowmemorykiller.c: backport 3.4 lowmemorykiller

All commits up to:
    f8f24e6  lowmemorykiller: make default lowmemorykiller debug message useful
RCU: Joe's RCU

Forward port jRCU to linux-3.0.

Thanks goes to Francisco Franco for his help
in testing out this version on the Android
Galaxy Nexus phone.

Signed-off-by: Joe Korty <joe.korty@ccur.com>