ASoC: wm8903: Remove outdated DMIC comment

Support for DMICs was added in commit 97945c46

 ("ASoC: WM8903:
Implement DMIC support"). Remove them from the TODO list at the top of
the driver.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20230328095819.1632802-1-ckeepax@opensource.cirrus.com


Signed-off-by: Mark Brown <broonie@kernel.org>