V4L/DVB (4869): Lgh06xf: use return value of dvb_pll_configure()

Use return value of dvb_pll_configure() to fill priv->frequency

In lgh06xf_set_params:
Rename int variable "err" to "result".
Remove needless calculation of the set frequency, since this value is now
being returned by dvb_pll_configure().

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