media: i2c: OV5647: change to use macro for the registers

ref docuemnt:
  ov5647-datasheet-v1.00-2009

Signed-off-by: Jacob Chen <jacob-chen@iotwrt.com>
Reviewed-by: Luis Oliveira <lolivei@synopsys.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>