dt-bindings: pinctrl: rt2880: add missing pin groups and functions

Add the missing pin groups:
jtag, wdt

Add the missing functions:
i2s, jtag, pcie refclk, pcie rst, pcm, spdif2, spdif3, wdt refclk, wdt rst

Sort pin groups and functions in alphabetical order. Fix a typo.

Signed-off-by: Arınç ÜNAL <[e-mail]>
Acked-by: Rob Herring <[e-mail]>
Acked-by: Sergio Paracuellos <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Linus Walleij <[e-mail]>

Documentation/devicetree/bindings/pinctrl/ralink,rt2880-pinmux.yaml

···
   - Sergio Paracuellos <[e-mail]>
 
 description:
-  The rt2880 pinmux can only set the muxing of pin groups. muxing indiviual pins
+  The rt2880 pinmux can only set the muxing of pin groups. Muxing indiviual pins
   is not supported. There is no pinconf support.
 
 properties:
···
         properties:
           groups:
             description: Name of the pin group to use for the functions.
-            enum: [i2c, spi, uart1, uart2, uart3, rgmii1, rgmii2, mdio,
-                   pcie, sdhci]
+            enum: [i2c, jtag, mdio, pcie, rgmii1, rgmii2, sdhci, spi,
+                   uart1, uart2, uart3, wdt]
           function:
             description: The mux function to select
-            enum: [gpio, i2c, spi, uart1, uart2, uart3, rgmii1, rgmii2,
-                   mdio, nand1, nand2, sdhci]
+            enum: [gpio, i2c, i2s, jtag, mdio, nand1, nand2, pcie refclk,
+                   pcie rst, pcm, rgmii1, rgmii2, sdhci, spdif2, spdif3,
+                   spi, uart1, uart2, uart3, wdt refclk, wdt rst]
 
         required:
           - groups