drm: sdi: xilinx: correcting multi link payload value

drm: sdi: xilinx: correcting multi link payload value

Channel bit have to be set only in case of multi link data.
In SDI-TX logicore IP, except 3GB mode all other modes are
single link only, hence these bit is redundant.
3GB mode is dual link.
For 3GB mode first link have to be programmed as channel 1,
and second link payload have to be programmed as channel 3.

Signed-off-by: Saurabh Sengar <saurabhs@xilinx.com>
Reviewed-by: Hyun Kwon <hyun.kwon@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>