[media] v4l: s5p-tv: hdmi: integrate with MHL

Adding support for using MHL (SiI9234 or other) chip if its configuration was
passed to HDMI by platfrom data.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>