media: ov9650: avoid maybe-uninitialized warnings

media: ov9650: avoid maybe-uninitialized warnings

The regmap change causes multiple warnings like

drivers/media/i2c/ov9650.c: In function 'ov965x_g_volatile_ctrl':
drivers/media/i2c/ov9650.c:889:29: error: 'reg2' may be used uninitialized in this function [-Werror=maybe-uninitialized]
   exposure = ((reg2 & 0x3f) << 10) | (reg1 << 2) |
              ~~~~~~~~~~~~~~~^~~~~~

It is apparently hard for the compiler to see here if ov965x_read()
returned successfully or not. Besides, we have a v4l2_dbg() statement
that prints an uninitialized value if regmap_read() fails.

Adding an 'else' clause avoids the ambiguity.

Fixes: 361f3803adfe ("media: ov9650: use SCCB regmap")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>