Revert "Force USB charging at 900mA"

This reverts commit 3710829dacbd7965ef7459b706cc9b071136e15b.
USB Fast Charge for Nexus 5

Increases input current limit to 900mA when charging via USB.
This patch does not force AC mode because this device is capable
of a charging at a much higher current limit than some USB ports
are able to deliver.

Conflicts:
	arch/arm/mach-msm/Makefile