[media] tda18271: delay IR & RF calibration until init() if delay_cal is set

if the configuration option 'delay_cal' is set, delay both IR & RF
calibration until init() is called.
both module option 'cal' or configuration option 'rf_cal_on_startup'
will override this delay. it makes no sense to mix 'delay_cal' with
'rf_cal_on_startup' as these options conflict with each other.

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