V4L/DVB (4948): Cxusb: Convert tuner functions to use dvb_pll_attach

Converted dee1601, lgz201 and dtt8579 to use dvb_pll_attach
in dvb-usb-cxusb.

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>