g1-hantro-plugin: enable RGB dithering for PostProcessor
g1-hantro-plugin: enable RGB dithering for PostProcessor

Signed-off-by: Bo Shen <b3e6a3251704a94eee1cf08e0adc382e6cb535ee@atmel.com>

commshare/gst1-hantro-g1,commshare/gst1-hantro-g1,linux4sam/gst1-hantro-g1,linux4sam/gst1-hantro-g1