[media] v4l: remove MEDIA_TUNER dependency for VIDEO_TUNER

[media] v4l: remove MEDIA_TUNER dependency for VIDEO_TUNER

em28xx selects VIDEO_TUNER, which has a dependency on MEDIA_TUNER,
so we get a Kconfig warning if that is disabled:

warning: (VIDEO_PVRUSB2 && 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)

VIDEO_TUNER does not actually depend on MEDIA_TUNER, and the
dependency does nothing except cause the above warning, so let's
remove it.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>