OMAPDSS: HDMI: Implement initialization of MCLK

When the MCLK is used to drive the Audio Clock Regeneration packets,
the initialization procedure is to set ACR_CTRL[2] to 0 and then
back again to 1. Also, devices that do not support the MCLK, use
the TMDS clock directly by leaving ACR_CTRL[2] set to 0.

The MLCK clock divisor, mclk_mode, is configured only if MLCK
is used. Such configuration is no longer related to the CTS mode
as in some silicon revisions CTS SW-mode is used along with the MCLK.

Signed-off-by: Ricardo Neri <ricardo.neri@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>