dt-bindings: arm: fsl: add TQ-Systems boards based on i.MX6Q/QP/DL

The TQ-Systems MBa6x mainboard can be used with TQMa6 variants with
i.MX6Q/QP/DL SoCs (TQMa6Q/QP/DL). The TQMa6Q and DL exist in two variants:
The newer variants "A" have a hardware workaround for Erratum ERR006687,
while variants "B" are missing such a workaround, so it needs to be
handled in software. The erratum was fixed in i.MX6QP, so no "A" variant
of the TQMa6QP exists.
Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Documentation/devicetree/bindings/arm/fsl.yaml

@@ -323,6 +323,20 @@ properties:
           - const: toradex,apalis_imx6q
           - const: fsl,imx6q
 
+      - description: TQ-Systems TQMa6Q SoM (variant A) on MBa6x
+        items:
+          - const: tq,imx6q-mba6x-a
+          - const: tq,mba6a               # Expected by bootloader, to be removed in the future
+          - const: tq,imx6q-tqma6q-a
+          - const: fsl,imx6q
+
+      - description: TQ-Systems TQMa6Q SoM (variant B) on MBa6x
+        items:
+          - const: tq,imx6q-mba6x-b
+          - const: tq,mba6b               # Expected by bootloader, to be removed in the future
+          - const: tq,imx6q-tqma6q-b
+          - const: fsl,imx6q
+
       - description: i.MX6QP based Boards
         items:
           - enum:
@@ -344,6 +358,13 @@ properties:
           - const: phytec,imx6qdl-pcm058  # PHYTEC phyCORE-i.MX6
           - const: fsl,imx6qp
 
+      - description: TQ-Systems TQMa6QP SoM on MBa6x
+        items:
+          - const: tq,imx6qp-mba6x-b
+          - const: tq,mba6b               # Expected by bootloader, to be removed in the future
+          - const: tq,imx6qp-tqma6qp-b
+          - const: fsl,imx6qp
+
       - description: i.MX6DL based Boards
         items:
           - enum:
@@ -482,6 +503,20 @@ properties:
           - const: dh,imx6s-dhcom-som
           - const: fsl,imx6dl
 
+      - description: TQ-Systems TQMa6DL SoM (variant A) on MBa6x
+        items:
+          - const: tq,imx6dl-mba6x-a
+          - const: tq,mba6a               # Expected by bootloader, to be removed in the future
+          - const: tq,imx6dl-tqma6dl-a
+          - const: fsl,imx6dl
+
+      - description: TQ-Systems TQMa6DL SoM (variant B) on MBa6x
+        items:
+          - const: tq,imx6dl-mba6x-b
+          - const: tq,mba6b               # Expected by bootloader, to be removed in the future
+          - const: tq,imx6dl-tqma6dl-b
+          - const: fsl,imx6dl
+
       - description: i.MX6SL based Boards
         items:
           - enum: