ASoC: fsl: define a common DRIVER_NAME

Instead of copying the driver name manually, use a common define.
No functional change.

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Acked-by: Shengjiu Wang <shengjiu.wang@gmail.com>
Link: https://lore.kernel.org/r/20230316123611.3495597-1-alexander.stein@ew.tq-group.com


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