fastcharge: initial adaptation for Nexus 4

Signed-off-by: Paul Reioux <reioux@gmail.com>

Conflicts:
	arch/arm/mach-msm/Kconfig
	arch/arm/mach-msm/fastchg.c
	drivers/power/pm8921-charger.c
	drivers/usb/otg/msm_otg.c