m8: Better mount options to improve performance

Change-Id: Id539c7b7a6086034b491efa3729dd4c5e9524393
m8: add volume rocker wake support

Change-Id: Icaa2c4659c919f392f5c44cc66f21696f83a720f
init: set readhead buffer to 512kb on mmcblk1 as well

Change-Id: I181b75c68cee729b98ab90b548518ab7d9cce6cb