ARM: dts: msm: Set the default mode for USB on SA8195P

The SA8195P target requires the primary USB controller
to run in host mode. Add the property to set the mode
of the primary USB controller to host on the SA8195P target.

Change-Id: If525fc7b10a893a69e7317577efb94f193cade66
Signed-off-by: Anant Goel <anantg@codeaurora.org>