[media] tuners/Kconfig: fix build when just DTV or SDR is enabled

[media] tuners/Kconfig: fix build when just DTV or SDR is enabled

As reported by Kbuildtest:
	warning: (VIDEO_PVRUSB2 && VIDEO_TLG2300 && VIDEO_USBVISION && VIDEO_GO7007 && VIDEO_AU0828_V4L2 && VIDEO_CX231XX && VIDEO_TM6000 && VIDEO_EM28XX && VIDEO_IVTV && VIDEO_MXB && VIDEO_CX18 && VIDEO_CX23885 && VIDEO_CX88 && VIDEO_BT848 && VIDEO_SAA7134 && VIDEO_SAA7164) selects VIDEO_TUNER which has unmet direct dependencies (MEDIA_SUPPORT && MEDIA_TUNER)

That happens when:

	# CONFIG_MEDIA_ANALOG_TV_SUPPORT is not set
	CONFIG_MEDIA_DIGITAL_TV_SUPPORT=y
	# CONFIG_MEDIA_RADIO_SUPPORT is not set
	# CONFIG_MEDIA_SDR_SUPPORT is not set
	CONFIG_VIDEO_AU0828_V4L2=y
	CONFIG_VIDEO_CX231XX=y
	CONFIG_VIDEO_TM6000=y
	CONFIG_VIDEO_EM28XX=y
	CONFIG_VIDEO_TUNER=y
	CONFIG_MEDIA_SUPPORT=y

With means that we need to enable MEDIA_TUNER also when DTV
is enabled. While the above config doesn't cover, if we enable
SDR, the same error can also happen.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>