media: tegra-cec: fix messy probe() cleanup

The probe() cleanup code ('goto foo_error') was very messy. It appears
that this code wasn't updated when I switched to the devm_ functions
in an earlier version.

Update the code to use 'return error' where it can and do proper cleanup
where it needs to.

Note that the original code wasn't buggy, it was just messy.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>