ASoC: meson: axg-tdmout: right_j is not supported

Right justified format is actually not supported by the amlogic tdm output
encoder.

Fixes: c41c2a35 ("ASoC: meson: add tdm output driver")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Mark Brown <broonie@kernel.org>