Nexus 6: USB fastcharge only with SDP connection

Conflicts:
	drivers/power/smb135x-charger.c
msm_thermal: throttle cpu freq at high temps

Clean and simple, thanks @franciscofranco
Based on https://github.com/franciscofranco/hammerhead/commit/ce8a51b1eeedb0d11a1df3f7e74375e836ba88dd