spi: dt-bindings: amlogic, meson-gx-spicc: Add pinctrl names for SPI signal states

SPI pins of the SPICC Controller in Meson-GX needs to be controlled by
pin biais when idle. Therefore define three pinctrl names:
- default: SPI pins are controlled by spi function.
- idle-high: SCLK pin is pulled-up, but MOSI/MISO are still controlled
by spi function.
- idle-low: SCLK pin is pulled-down, but MOSI/MISO are still controlled
by spi function.
Reported-by: Da Xue <da@libre.computer>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Amjad Ouled-Ameur <aouledameur@baylibre.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20221004-up-aml-fix-spi-v4-1-0342d8e10c49@baylibre.comSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/spi/amlogic,meson-gx-spicc.yaml

@@ -10,9 +10,6 @@ title: Amlogic Meson SPI Communication Controller
 maintainers:
   - Neil Armstrong <neil.armstrong@linaro.org>
 
-allOf:
-  - $ref: "spi-controller.yaml#"
-
 description: |
   The Meson SPICC is a generic SPI controller for general purpose Full-Duplex
   communications with dedicated 16 words RX/TX PIO FIFOs.
@@ -43,14 +40,16 @@ properties:
     minItems: 1
     maxItems: 2
 
-if:
+allOf:
+  - $ref: "spi-controller.yaml#"
+  - if:
       properties:
         compatible:
           contains:
             enum:
               - amlogic,meson-g12a-spicc
 
-then:
+    then:
       properties:
         clocks:
           minItems: 2
@@ -60,7 +59,7 @@ then:
             - const: core
             - const: pclk
 
-else:
+    else:
       properties:
         clocks:
           maxItems: 1
@@ -69,6 +68,26 @@ else:
           items:
             - const: core
 
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - amlogic,meson-gx-spicc
+
+    then:
+      properties:
+        pinctrl-0: true
+        pinctrl-1: true
+        pinctrl-2: true
+
+        pinctrl-names:
+          minItems: 1
+          items:
+            - const: default
+            - const: idle-high
+            - const: idle-low
+
 required:
   - compatible
   - reg