[media] xc4000: check_firmware() cleanup

This patch makes the following fixes in check_firmware():
  - there is only one BASE and INIT1 firmware for XC4000
  - loading SCODE is needed also for FM radio

Signed-off-by: Istvan Varga <istvan_v@mailbox.hu>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>