[media] ts2020: use customise option correctly

The Kconfig entry for "TS2020 based tuners" defaults to modular if
DVB_FE_CUSTOMISE is set. But that Kconfig symbol was replaced with
MEDIA_SUBDRV_AUTOSELECT as of v3.7. So use the new symbol. And negate
the logic, so we are in line with all the similar entries in this file.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>