media: tc358746: Address compiler warnings

Address these compiler warnings by initialising the m_best and p_best
values to 0 and 1 respectively (as latter is used as a divisor):

   drivers/media/i2c/tc358746.c: In function 'tc358746_find_pll_settings':
>> drivers/media/i2c/tc358746.c:817:13: warning: 'p_best' is used uninitialized
[-Wuninitialized]
     817 |         u16 p_best, p;
         |             ^~~~~~
>> drivers/media/i2c/tc358746.c:816:13: warning: 'm_best' is used uninitialized
[-Wuninitialized]
     816 |         u16 m_best, mul;
         |             ^~~~~~

The warnings may well be a false positive but it is difficult for a
compiler to find out whether that truly is the case.

Closes: https://lore.kernel.org/oe-kbuild-all/202305301627.fLT3Bkds-lkp@intel.com/

Reported-by: kernel test robot <lkp@intel.com>
Fixes: 80a21da ("media: tc358746: add Toshiba TC358746 Parallel to CSI-2 bridge driver")
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Marco Felsch <m.felsch@pengutronix.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

Author: Sakari Ailus

drivers/media/i2c/tc358746.c

@@ -813,8 +813,8 @@ static unsigned long tc358746_find_pll_settings(struct tc358746 *tc358746,
 	u32 min_delta = 0xffffffff;
 	u16 prediv_max = 17;
 	u16 prediv_min = 1;
-	u16 m_best, mul;
-	u16 p_best, p;
+	u16 m_best = 0, mul;
+	u16 p_best = 1, p;
 	u8 postdiv;
 
 	if (fout > 1000 * HZ_PER_MHZ) {