dt-bindings: mmc: sdhci-am654: add ti,itap-del-sel-ddr50 to schema

Add missing ti,itap-del-sel-ddr50 property to schema to clear up the
following warnings.

mmc@4fb0000: Unevaluated properties are not allowed ('ti,itap-del-sel-ddr50' was unexpected)
Signed-off-by: Matt Ranostay <mranostay@ti.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20221013024021.121104-1-mranostay@ti.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Documentation/devicetree/bindings/mmc/sdhci-am654.yaml

@@ -159,6 +159,12 @@ properties:
     minimum: 0
     maximum: 0x1f
 
+  ti,itap-del-sel-ddr50:
+    description: Input tap delay for MMC DDR50 timing
+    $ref: "/schemas/types.yaml#/definitions/uint32"
+    minimum: 0
+    maximum: 0x1f
+
   ti,itap-del-sel-ddr52:
     description: Input tap delay for MMC DDR52 timing
     $ref: "/schemas/types.yaml#/definitions/uint32"