ramips: further improve support for Xiaomi MiWiFi Nano

This patch does the following:

- prepend vendor name to model
- set status LEDs to follow the behavior in stock FW
- simplify state_default node definition
- use generic name for flash node

Stock FW status indicators:
https://files.xiaomi-mi.com/files/Mi_Router_Wi-Fi_Nano/Mi_router-NANO_EN.pdf
> Yellow: power on / off
> Blue: during normal operation
> Red: in case of problems with the operation of the device

Signed-off-by: Sungbo Eo <mans0n@gorani.run>

target/linux/ramips/dts/mt7628an_xiaomi_miwifi-nano.dts

@@ -7,13 +7,13 @@
 
 / {
 	compatible = "xiaomi,miwifi-nano", "mediatek,mt7628an-soc";
-	model = "MiWiFi Nano";
+	model = "Xiaomi MiWiFi Nano";
 
 	aliases {
-		led-boot = &led_blue;
-		led-failsafe = &led_blue;
-		led-running = &led_blue;
-		led-upgrade = &led_blue;
+		led-boot = &led_status_amber;
+		led-failsafe = &led_status_red;
+		led-running = &led_status_blue;
+		led-upgrade = &led_status_amber;
 	};
 
 	chosen {
@@ -23,17 +23,17 @@
 	leds {
 		compatible = "gpio-leds";
 
-		led_blue: status_blue {
+		led_status_blue: status_blue {
 			label = "miwifi-nano:blue:status";
 			gpios = <&gpio0 11 GPIO_ACTIVE_LOW>;
 		};
 
-		status_red {
+		led_status_red: status_red {
 			label = "miwifi-nano:red:status";
 			gpios = <&gpio1 5 GPIO_ACTIVE_LOW>;
 		};
 
-		status_amber {
+		led_status_amber: status_amber {
 			label = "miwifi-nano:amber:status";
 			gpios = <&gpio1 12 GPIO_ACTIVE_LOW>;
 		};
@@ -50,12 +50,10 @@
 	};
 };
 
-&pinctrl {
-	state_default: pinctrl0 {
-		gpio {
-			ralink,group = "gpio", "refclk", "wdt", "wled_an";
-			ralink,function = "gpio";
-		};
+&state_default {
+	gpio {
+		ralink,group = "gpio", "refclk", "wdt", "wled_an";
+		ralink,function = "gpio";
 	};
 };
 
@@ -79,7 +77,7 @@
 &spi0 {
 	status = "okay";
 
-	m25p80@0 {
+	flash@0 {
 		compatible = "jedec,spi-nor";
 		reg = <0>;
 		spi-max-frequency = <40000000>;