Change au0828 to check if tuner is free or not before changing tuner
configuration.

vidioc_g_tuner(), and au0828_v4l2_close() now call v4l-core interface
v4l_enable_media_source() before changing tuner configuration.

Remove au0828_enable_analog_tuner() as it is no longer needed because
v4l2-core implements common interfaces to check for media source
availability.

In addition, queue_setup() no longer needs the tuner availability check
since v4l2-core does it.
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>