dt-bindings: leds: Add FUNCTION defines for per-band WLANs

Most wireless routers and access points can operate in multiple bands
simultaneously. Vendors often equip their devices with per-band LEDs.

Add defines for those very common functions to allow cleaner & clearer
bindings.
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20240117151736.27440-1-zajec5@gmail.comSigned-off-by: Lee Jones <lee@kernel.org>

include/dt-bindings/leds/common.h

@@ -101,6 +101,9 @@
 #define LED_FUNCTION_USB "usb"
 #define LED_FUNCTION_WAN "wan"
 #define LED_FUNCTION_WLAN "wlan"
+#define LED_FUNCTION_WLAN_2GHZ "wlan-2ghz"
+#define LED_FUNCTION_WLAN_5GHZ "wlan-5ghz"
+#define LED_FUNCTION_WLAN_6GHZ "wlan-6ghz"
 #define LED_FUNCTION_WPS "wps"
 
 #endif /* __DT_BINDINGS_LEDS_H */