In order to have the usb phy work in gadget mode, override
the default host mode with otg mode.

This allows gadget mode to work w/o any hacks to the dtsi file.

Cc: Rob Herring <robh+dt@kernel.org>
Cc: Andy Gross <agross@codeaurora.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Stephen Boyd <stephen.boyd@linaro.org>
Cc: linux-arm-msm@vger.kernel.org
Cc: devicetree@vger.kernel.org
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>