[media] V4L: marvell-ccic: (cosmetic) remove redundant variable assignment

The "ret = 0" assignment in mcam_vidioc_s_fmt_vid_cap() is redundant,
because at that location "ret" is anyway guaranteed to be == 0.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>