Now, it outputs:

[10927.639641] drxk: SCU_RESULT_INVPAR while sending cmd 0x0203 with params:
[10927.646283] drxk: 02 00 00 00 10 00 07 00 03 02                    ..........

Better than ERROR -3. This happens with Terratec H5 firmware.

It adds 2 new error conditions, and something useful to track
what the heck is that.

I suspect that the scu_command is dependent on the firmware
revision.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>