dt-bindings: mmc: mtk-sd: increase reg items

MediaTek has a new version of mmc IP since mt8183. Some IO registers
are moved to top to improve hardware design and named as "host top
registers".

Add host top register in the reg binding description for mt8183 and
successors.

Signed-off-by: Wenbin Mei <[e-mail]>
Signed-off-by: Tinghan Shen <[e-mail]>
Reviewed-by: Rob Herring <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Ulf Hansson <[e-mail]>

Documentation/devicetree/bindings/mmc/mtk-sd.yaml

···
           - const: mediatek,mt8183-mmc
 
   reg:
-    maxItems: 1
+    minItems: 1
+    items:
+      - description: base register (required).
+      - description: top base register (required for MT8183).
 
   clocks:
     description:
···
   - pinctrl-1
   - vmmc-supply
   - vqmmc-supply
+
+if:
+  properties:
+    compatible:
+      contains:
+        const: mediatek,mt8183-mmc
+then:
+  properties:
+    reg:
+      minItems: 2
 
 unevaluatedProperties: false