ARM: dts: msm: Add vls_clamp_reg for TRINKET

PHY level shifters are clamped by asserting
usb3_phy_vls_clamp_en. This is required for phy to perform
autonomous detection. Add vls_clamp_reg base address
so that driver can assert the clamp register when
enabling autonomous mode.

Change-Id: I1d628a7eccba037c251cc581d11eec8257ff2f63
Signed-off-by: Sriharsha Allenki <sallenki@codeaurora.org>