media: ov5645: Supported external clock is 24MHz

The external clock frequency was set to 23.88MHz by mistake
because of a platform which cannot get closer to 24MHz.
The supported by the driver external clock is 24MHz so
set it correctly and also fix the values of the pixel
clock and link clock.
However allow 1% tolerance to the external clock as this
difference is small enough to be insignificant.

Signed-off-by: Todor Tomov <todor.tomov@linaro.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>