[media] xc5000: fix incorrect debug printnk

[media] xc5000: fix incorrect debug printnk

I found very small bug in xc5000 source. When set option debug=1 and
listen a radio we see in dmesg xc5000: xc_SetTVStandard()
Standard = M/N-NTSC/PAL-BTSC at all times. However, it should be, instead
"FM Radio-INPUT1_MONO".

That happens because xc5000_set_radio_freq() gets the correct value for
VideoMode and AudioMode for radio and calls xc_SetTVStandard() where name
of standard comes from the incorrect place priv->video_standard.

This incorrect debug message makes debugging  a little difficult.

Signed-off-by: Dmitry Belimov <d.belimov@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>