ramips: use blue status LED for Xiaomi Router 3G

The blue LED is what other firmwares use for this device, and it's a lot
easier on the eyes than its shade of yellow, which implies an error
condition.

Signed-off-by: Daniel Gimpelevich <daniel@gimpelevich.san-francisco.ca.us>
[merge into existing $boardname:blue:status block]
Signed-off-by: Mathias Kresin <dev@kresin.me>
Acked-by: Piotr Dymacz <pepe2k@gmail.com>
Acked-by: Cezary Jackiewicz <cezary@eko.one.pl>

target/linux/ramips/base-files/etc/diag.sh

@@ -174,6 +174,7 @@ get_status_led() {
 		;;
 	k2p|\
 	m3|\
+	mir3g|\
 	miwifi-nano)
 		status_led="$boardname:blue:status"
 		;;
@@ -190,9 +191,6 @@ get_status_led() {
 	m4-8M)
 		status_led="m4:blue:status"
 		;;
-	mir3g)
-		status_led="$boardname:yellow:status"
-		;;
 	miwifi-mini|\
 	zte-q7)
 		status_led="$boardname:red:status"