pinctrl: airoha: fix pinctrl function mismatch issue

The blamed commit made the following changes:

-#define PINCTRL_FUNC_DESC(id)...
-		.desc = PINCTRL_PINFUNCTION(#id, ...
+#define PINCTRL_FUNC_DESC(id, table)...
+		.desc = PINCTRL_PINFUNCTION(#id, ...

-	PINCTRL_FUNC_DESC(pon)...
+	PINCTRL_FUNC_DESC("pon", pon)...

It's clear that the id of funcs doesn't match the definition.
Remove redundant #string from the definition to fix this issue:
pinctrl-airoha ...: invalid function mdio in map table

Fixes: 4043b0c ("pinctrl: airoha: generalize pins/group/function/confs handling")
Signed-off-by: Chukun Pan <amadeus@jmu.edu.cn>
Acked-by: Christian Marangi <ansuelsmth@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Author: aiamadeus

drivers/pinctrl/mediatek/pinctrl-airoha.c

@@ -35,7 +35,7 @@
 
 #define PINCTRL_FUNC_DESC(id, table)					\
 	{								\
-		.desc = PINCTRL_PINFUNCTION(#id, table##_groups,	\
+		.desc = PINCTRL_PINFUNCTION(id, table##_groups,	\
 					    ARRAY_SIZE(table##_groups)),\
 		.groups = table##_func_group,				\
 		.group_size = ARRAY_SIZE(table##_func_group),		\