media: cxd2841er: use DIV_ROUND_UP to calculate timeout

Don't open-code DIV_ROUND_UP() kernel macro.

Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>