media: ov5647: Fix style issues

The driver has some obvious style issues which are worth fixing before
expanding the driver capabilities.

Fix:
- Variable declaration order
- Function parameters alignment
- Multi-line comments and spurious line breaks
- Use lowercase for hexadecimal values
- > 80 cols lines

Cosmetic change, no functional changes intended.

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>