[media] Kconfig: fix breakages when DVB_CORE is not selected
    
    On some weird randconfigs, it is possible to select DVB
    drivers, without having the DVB_CORE:
    
    CONFIG_DVB_AU8522=m
    CONFIG_DVB_AU8522_V4L=m
    CONFIG_DVB_TUNER_DIB0090=m
    
    This was never supposed to work, but changeset 22a613e89825
    ("[media] dvb_frontend: merge duplicate dvb_tuner_ops.release implementations")
    caused it to be exposed:
    
       drivers/built-in.o: In function `fc0011_attach':
       (.text+0x1598fb): undefined reference to `dvb_tuner_simple_release'
       drivers/built-in.o:(.rodata+0x55e58): undefined reference to `dvb_tuner_simple_release'
       drivers/built-in.o:(.rodata+0x57398): undefined reference to `dvb_tuner_simple_release'
    
    Fixes: 22a613e89825 ("[media] dvb_frontend: merge duplicate dvb_tuner_ops.release implementations")
    Reported-by: kbuild test robot <fengguang.wu@intel.com>
    Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>