drm/omap: Add infoframe & dvi/hdmi mode support

Make the omapdrm driver use the new HDMI ops when possible.

omapdrm will call set_hdmi_mode (when available) to tell the encoder
driver whether the monitor is a DVI or HDMI monitor, and if it's an HDMI
monitor, omapdrm will call set_hdmi_infoframe to to set the AVI
infoframe.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Rob Clark <robdclark@gmail.com>