ASoC: rx51: Correct DAPM route for capture

"Mic Bias" is DAPM_SUPPLY so it has to be connected in the route
accordingly.
Fixes audio capture on the board.

Reported-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Tested-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Mark Brown <broonie@kernel.org>