usb: dwc3: fix the error returned with usb3_phy failure

commit 315955d707b50c8aad20a32ec0dd4c9fe243cabe upstream.

When there is an error with the usb3_phy probe or absence, the error returned
is erroneously for usb2_phy.

Signed-off-by: Ruchika Kharwar <ruchika@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>