dt-bindings: phy: mediatek: tphy: support software efuse load

Add optional property nvmem-cells and nvmem-cell-names to support
software efuse load, this helps to fix the efuse bit shift issue
on mt8195 etc.
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/20211218082802.5256-1-chunfeng.yun@mediatek.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

Documentation/devicetree/bindings/phy/mediatek,tphy.yaml

@@ -160,6 +160,24 @@ patternProperties:
                 - PHY_TYPE_PCIE
                 - PHY_TYPE_SATA
 
+      nvmem-cells:
+        items:
+          - description: internal R efuse for U2 PHY or U3/PCIe PHY
+          - description: rx_imp_sel efuse for U3/PCIe PHY
+          - description: tx_imp_sel efuse for U3/PCIe PHY
+        description: |
+          Phandles to nvmem cell that contains the efuse data;
+          Available only for U2 PHY or U3/PCIe PHY of version 2/3, these
+          three items should be provided at the same time for U3/PCIe PHY,
+          when use software to load efuse;
+          If unspecified, will use hardware auto-load efuse.
+
+      nvmem-cell-names:
+        items:
+          - const: intr
+          - const: rx_imp
+          - const: tx_imp
+
       # The following optional vendor properties are only for debug or HQA test
       mediatek,eye-src:
         description: