media: pvrusb2: fix DVB_CORE dependency

Now that DVB_CORE can be a loadable module, pvrusb2 can run into
a link error:

ld.lld: error: undefined symbol: dvb_module_probe
>>> referenced by pvrusb2-devattr.c
>>>               drivers/media/usb/pvrusb2/pvrusb2-devattr.o:(pvr2_lgdt3306a_attach) in archive vmlinux.a
ld.lld: error: undefined symbol: dvb_module_release
>>> referenced by pvrusb2-devattr.c
>>>               drivers/media/usb/pvrusb2/pvrusb2-devattr.o:(pvr2_dual_fe_attach) in archive vmlinux.a

Refine the Kconfig dependencies to avoid this case.

Link: https://lore.kernel.org/linux-media/20230117171055.2714621-1-arnd@kernel.org


Fixes: 7655c342 ("media: Kconfig: Make DVB_CORE=m possible when MEDIA_SUPPORT=y")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>