ARM: msm: dts: Add a USB OTG regulator for APQ8084 liquid

USB OTG is powered via a TPD4S214 chip. This is enabled via
PMIC gpio 8. Add device definition for this.

Add additional USB specific handle for hdmi_vreg.

Change-Id: I4a742571251f12f5c9d1b20065996d2292e6cdbf
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>