ramips: use m25p,fast-read on Xiaomi Mi Router 4A Gb/3G v2

The Xiaomi Mi Router 4A Gigabit model has a race condition on bootup
causing the SQUASHFS data errors to appear and create a bootloop
scenario.

Adding the m25p,fast-read property resolves this issue.

Suggested-by: David Bentham <[email protected]>
Signed-off-by: Adrian Schmutzler <[email protected]>

target/linux/ramips/dts/mt7621_xiaomi_mi-router-4a-3g-v2.dtsi

@@ -50,6 +50,7 @@
 		compatible = "jedec,spi-nor";
 		reg = <0>;
 		spi-max-frequency = <80000000>;
+		m25p,fast-read;
 
 		partitions {
 			compatible = "fixed-partitions";