drm/i915/tv: fix gen4 composite s-video tv-out

drm/i915/tv: fix gen4 composite s-video tv-out

This is *not* bisected, but the likely regression is

commit a7d74d285054b6b0f9cf3d05fb0648fac28185c9
Author: Zhao Yakui <yakui.zhao@intel.com>
Date:   Tue Nov 24 09:48:48 2009 +0800

    drm/i915: Don't set up the TV port if it isn't in the BIOS table.

The commit does not check for all TV device types that might be present
in the VBT, disabling TV out for the missing ones. Add composite
S-video.

Reported-and-tested-by: Matthew Khouzam <matthew.khouzam@gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=73362
Cc: stable@vger.kernel.org
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>