[media] rtl820t: Add a debug msg when PLL gets locked

	[ 2255.342797] r820t 3-001a: generic_set_freq: PLL locked on frequency 725476191 Hz, gain=45

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