[media] lgdt330x: warn on errors blasting modulation config to the lgdt3303

fix the following build warning:

lgdt330x.c: In function "lgdt330x_set_parameters":
lgdt330x.c:346:6: warning: variable "err" set but not used
[-Wunused-but-set-variable]

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