V4L/DVB (5637): Cx88: kill core->pll_desc and core->pll_addr

Now that dvb-pll is being used properly in all cx88-dvb instances,
the cx88 driver no longer needs to store pll_desc nor pll_addr.

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