V4L/DVB (13262): tda18271: fix regression preventing std map override from taking effect

In the changeset entitled, "tda18271: add support for the set_config method",
the initialization order was changed such that the standard map overrides
were being applied before loading the default standard map, based on the
stepping of the silicon.  This changeset restores the proper order by
processing the standard map overrides both within the tda18271_set_config()
and the tda18271_attach() functions, after we read the id register of the
tuner.

Thanks to Michael Obst for his testing, helping me to identify the regression.

Signed-off-by: Michael Krufky <mkrufky@kernellabs.com>
Signed-off-by: Michael Obst <mike.obst@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>