media: atomisp: get rid of some old broken debug code

It sounds that someone once changed the debug level at compile
time for some testing, but forgot to remove the legacy code after
finishing debuging it.

Get rid of the dead code.

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