drm: detect hdmi monitor by hdmi identifier (v3)

drm: detect hdmi monitor by hdmi identifier (v3)

Sometime we need to communicate with HDMI monitor by sending audio or video
info frame, so we have to know monitor type. However if user utilize HDMI-DVI adapter to connect DVI monitor, hardware detection will incorrectly show the monitor is HDMI. HDMI spec tell us that any device containing IEEE registration Identifier will be treated as HDMI device.  The patch intends to detect HDMI monitor by this rule.

Signed-off-by: Ma Ling <ling.ma@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>