INTERNAL: Correct the USB PHY and Connector for Mistral

Mistral board has only one USB type C connector, its
connected to USB2 controller. Update the correct the dts to match
the mistral platform

Signed-off-by: Khasim Syed Mohammed <khasim.mohammed@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
Change-Id: I4ee010ea353fad74dfb478c6d4e62394398cffff