dt-bindings: spi: add compatibles for mt7988

MT7988 has 2 different spi controllers. Add their compatibles.

Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20241109105029.52748-1-linux@fw-web.de
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: frank-w

Documentation/devicetree/bindings/spi/mediatek,spi-mt65xx.yaml

@@ -35,6 +35,8 @@ properties:
           - enum:
               - mediatek,mt7981-spi-ipm
               - mediatek,mt7986-spi-ipm
+              - mediatek,mt7988-spi-quad
+              - mediatek,mt7988-spi-single
               - mediatek,mt8188-spi-ipm
           - const: mediatek,spi-ipm
       - items: