SDIO: Enable power saving mode

Change-Id: If8989c209835b3d97658950e7b4053974aec29d2
block: separate priority boosting from REQ_META

Add a new REQ_PRIO to let requests preempt others in the cfq I/O schedule,
and lave REQ_META purely for marking requests as metadata in blktrace.

All existing callers of REQ_META except for XFS are updated to also
set REQ_PRIO for now.

Backported to 3.0.101 by Ketut Putu Kumajaya <ketut.kumajaya@gmail.com>

Change-Id: I9df68c8ff5816e8793e73cd7321afc68c29552a9
p31xx/p51xx: Disable Samsung enhanced low memory killer

Suspect cause of battery drain on KitKat

Change-Id: Iab9ffffeb8ca7de58400568ac1356486eb7857bb
p51xx: Disable experimental P51xx Y-Cable support

Change-Id: I55d58fc47c9081d4e67ddf1b8cef9bc77f5a7e0e
bcmdhd: Restore previous 1.28.19.4 (RC2_1130) driver

Change-Id: If91ad148556f87b2910e54e69b26f5f110f84ebc