OMAPDSS: HDMI: Modify logic to configure MCLK

The MCLK mode defines a factor to divide the clock that is used to
generate the Audio Clock Regeneration packets, MCLK.

The divisor is not used when the CTS value is calculated by HW.
When the value is calculated by SW, it depends on the silicon
revision.

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