[media] az6007: Fix the number of parameters for QAM setup

Remove those warning messages:
[  121.696758] drxk: SCU_RESULT_INVPAR while sending cmd 0x0203 with params:
[  121.703401] drxk: 02 00 00 00 10 00 07 00 03 02                    ..........
[  121.703587] drxk: Warning -22 on QAMDemodulatorCommand

Acked-by: Antti Palosaari <crope@iki.fi>
Reviewed-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>