media: i2c: ds90ub953: Fix use of uninitialized variables

smatch reports some uninitialized variables:

drivers/media/i2c/ds90ub953.c:655 ub953_log_status() error: uninitialized symbol 'gpio_local_data'.
drivers/media/i2c/ds90ub953.c:655 ub953_log_status() error: uninitialized symbol 'gpio_input_ctrl'.
drivers/media/i2c/ds90ub953.c:655 ub953_log_status() error: uninitialized symbol 'gpio_pin_sts'.

These are used only for printing debug information, and the use of an
uninitialized variable only happens if an i2c transaction has failed,
which will print an error. Thus, fix the errors just by initializing the
variables to 0.

Closes: https://lore.kernel.org/all/8d6daeb1-b62a-bbb2-b840-8759c84f2085@xs4all.nl/

Fixes: 6363db1c ("media: i2c: add DS90UB953 driver")
Reported-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/media/i2c/ds90ub953.c

@@ -606,9 +606,9 @@ static int ub953_log_status(struct v4l2_subdev *sd)
 	u8 v = 0, v1 = 0, v2 = 0;
 	unsigned int i;
 	char id[UB953_REG_FPD3_RX_ID_LEN];
-	u8 gpio_local_data;
-	u8 gpio_input_ctrl;
-	u8 gpio_pin_sts;
+	u8 gpio_local_data = 0;
+	u8 gpio_input_ctrl = 0;
+	u8 gpio_pin_sts = 0;
 
 	for (i = 0; i < sizeof(id); i++)
 		ub953_read(priv, UB953_REG_FPD3_RX_ID(i), &id[i]);