[media] xc5000: be sure that the firmware is there before set params

Now that xc5000_set_params() is also called during resume,
move the code that checks for the firmware to happen there.

This way, the firmware will be loaded either for analog or
digital TV when .resume callback is called.

Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>