dt-bindings: display: mediatek: update supported chips

Add decriptions about supported chips, including MT2701 & MT8173

Signed-off-by: YT Shen <[e-mail]>
Acked-by: Rob Herring <[e-mail]>

Documentation/devicetree/bindings/display/mediatek/mediatek,disp.txt

···
 	"mediatek,<chip>-dpi"        - DPI controller, see mediatek,dpi.txt
 	"mediatek,<chip>-disp-mutex" - display mutex
 	"mediatek,<chip>-disp-od"    - overdrive
+  the supported chips are mt2701 and mt8173.
 - reg: Physical base address and length of the function block register space
 - interrupts: The interrupt signal from the function block (required, except for
   merge and split function blocks).
···
 	"mediatek,<chip>-disp-ovl"
 	"mediatek,<chip>-disp-rdma"
 	"mediatek,<chip>-disp-wdma"
+  the supported chips are mt2701 and mt8173.
 - larb: Should contain a phandle pointing to the local arbiter device as defined
   in Documentation/devicetree/bindings/memory-controllers/mediatek,smi-larb.txt
 - iommus: Should point to the respective IOMMU block with master port as

Documentation/devicetree/bindings/display/mediatek/mediatek,dsi.txt

···
 
 Required properties:
 - compatible: "mediatek,<chip>-dsi"
+  the supported chips are mt2701 and mt8173.
 - reg: Physical base address and length of the controller's registers
 - interrupts: The interrupt signal from the function block.
 - clocks: device clocks
···
 
 Required properties:
 - compatible: "mediatek,<chip>-mipi-tx"
+  the supported chips are mt2701 and mt8173.
 - reg: Physical base address and length of the controller's registers
 - clocks: PLL reference clock
 - clock-output-names: name of the output clock line to the DSI encoder