Call usb_phy_generic_unregister() if of_platform_populate() fails.

Fixes: d6299b6e ("usb: musb: Add support of CPPI 4.1 DMA controller to DA8xx")
Cc: stable <stable@kernel.org>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/69af1b1d-d3f4-492b-bcea-359ca5949f30@moroto.mountainSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>