mt76x0u: fix suspend/resume

We need to reset MCU and do other initializations on resume otherwise
MT7610U device will fail to initialize, what cause system hung due to
USB requests timeouts.

Patch fixes 4.19 -> 4.20 regression.

Cc: stable@vger.kernel.org # 4.20+
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>