[media] SoC Camera: ov6650: minor cleanups

This is a followup patch that addresses two minor issues left in the recently
added ov6650 sensor driver, as I've promised to the subsystem maintainer:
- remove a pair of extra brackets,
- drop useless case for not possible v4l2_mbus_pixelcode enum value of 0.

Created against linux-2.6.37-rc1.

Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>