usb: dwc3-meson-g12a: always configure dr-mode

dwc3_meson_g12a_force_mode() sets the dr-mode of the USB PHY. However
it skips setting the mode if it matches the one done during driver probe
(stored in private structure). This fails if the mode has been changed
to other value and then back to initial one. Fix this by configuring the
dr-mode always, regadless of the one set at the driver probe).

This fixes operation of USB gadget based drivers when they are initialized
for the second time.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>