V4L/DVB (9623): tvaudio: Improve debug msg by printing something more human

Before the patch, the used ioctl were printed as an hexadecimal code,
hard to be understand without consulting the way _IO macros work.
Instead, use the V4L default handler for printing such errors into a way
that would be easier to understand.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>