If no suitable DMA configuration is available, a previous 'bdc_phy_init()'
call must be undone by a corresponding 'bdc_phy_exit()' call.
Branch to the existing error handling path instead of returning
directly.
Fixes: cc29d4f67757 ("usb: bdc: Add support for USB phy")
Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>