[media] ov13858: Use do_div() for dividing a 64-bit number

ov13858 contained a 64-bit division. Use do_div() for calculating it.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Tested-by: Chiranjeevi Rapolu <chiranjeevi.rapolu@intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>