media: allegro: fix reset if WAKEUP has not been set properly

The Zynq UltraScale+ Devices Register Reference states that the WAKEUP
bit "should be set to 0 after the MCU sleep status bit gets back to 0."
If this is not done, the mcu is not going to sleep on reset and fail the
reset.

Set WAKEUP to 0 before triggering a reset to make sure that the reset is
successful.
Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/staging/media/allegro-dvt/allegro-core.c

@@ -1990,6 +1990,14 @@ static int allegro_mcu_reset(struct allegro_dev *dev)
 {
 	int err;
 
+	/*
+	 * Ensure that the AL5_MCU_WAKEUP bit is set to 0 otherwise the mcu
+	 * does not go to sleep after the reset.
+	 */
+	err = regmap_write(dev->regmap, AL5_MCU_WAKEUP, 0);
+	if (err)
+		return err;
+
 	err = regmap_write(dev->regmap,
 			   AL5_MCU_RESET_MODE, AL5_MCU_RESET_MODE_SLEEP);
 	if (err < 0)