usb: chipidea: udc: don't touch DP when controller is in host mode

usb: chipidea: udc: don't touch DP when controller is in host mode

[ Upstream commit c4e94174983a86c935be1537a73e496b778b0287 ]

When the controller is configured to be dual role and it's in host mode,
if bind udc and gadgt driver, those gadget operations will do gadget
disconnect and finally pull down DP line, which will break host function.

Cc: <stable@vger.kernel.org> # 4.1+
Signed-off-by: Li Jun <jun.li@nxp.com>
Signed-off-by: Peter Chen <peter.chen@nxp.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>