media: ov5640: fix get_light_freq on auto

media: ov5640: fix get_light_freq on auto

Light frequency was not properly returned when in auto
mode and the detected frequency was 60Hz.

Fixes: 19a81c1426c1 ("[media] add Omnivision OV5640 sensor driver")
Cc: stable@vger.kernel.org
Signed-off-by: Sam Bobrowicz <sam@elite-embedded.com>
Signed-off-by: Michal Simek <michal.simek@amd.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>