ASoC: dt-bindings: Drop imx-audio-sgtl5000.txt

The "fsl,imx-audio-sgtl5000" binding is already covered by
fsl-asoc-card.yaml, so remove the old text binding.

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20250807214358.4172451-1-robh@kernel.org


Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Mark Brown <broonie@kernel.org>