ARM: dts: msm: Add extcon for USB on trinket

Add pmi632_charger node as extcon for USB on trinket
to support dynamic switch between host and peripheral
using extcon based VBUS and ID notifications from
PMI632.

Change-Id: I2423439833587c71781e01ba052237bf94ac04bb
Signed-off-by: Sriharsha Allenki <sallenki@codeaurora.org>