media: adv7511/cobalt: rename driver name to adv7511-v4l2

Commit b2ce5617 ("media: i2c: fix warning same module names")
renamed the adv7511 module in the media tree to adv7511-v4l2.

This patch does the same rename for the driver name and device id to
keep the naming consistent.

Since the cobalt driver loads this module, it had to be renamed there
as well.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>