OMAPDSS: HDMI: OMAP4: Expand configuration for IEC-60958 audio

Utilize a snd_aes_iec958 struct to write the parameters of the IEC-60958
channel status word into the HDMI IP registers. Hence, the user of the
driver has full control of what parameters are written in the word.

Also, some of the parameters of the I2S structure have been removed
as they are actually IEC-60958 parameters.

Signed-off-by: Ricardo Neri <ricardo.neri@ti.com>