slimport: anx7808: add dynamic channel configuration

when contents channel number is changed, hdmi_rx_int_irq_handler
will config audio channel on slimport tx dynamically.

Change-Id: I55a0bb1dc9204ef8e16fd9acf5ed0c1969ce4982
Signed-off-by: cong.zhou <cong.zhou@lge.com>
Signed-off-by: Devin Kim <dojip.kim@lge.com>