mediatek: Xiaomi AX3000t: enable SPI calibration

Xiaomi enabled SPI calibration in new firmware:
- 1.0.84 and newer (rd03 model)
- 1.0.76 and newer (rd23 model)

This enables SPI calibration routines in OpenWrt too.

Tested-by: Aleksandr Danilov <sc16me@gmail.com>
Signed-off-by: Mikhail Zhilkin <csharper2005@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/17976
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

target/linux/mediatek/dts/mt7981b-xiaomi-mi-router-common.dtsi

@@ -315,6 +315,13 @@
 		compatible = "spi-nand";
 		reg = <0>;
 
+		spi-cal-enable;
+		spi-cal-mode = "read-data";
+		spi-cal-datalen = <7>;
+		spi-cal-data = /bits/ 8 <0x53 0x50 0x49 0x4e 0x41 0x4e 0x44>;
+		spi-cal-addrlen = <5>;
+		spi-cal-addr = /bits/ 32 <0x0 0x0 0x0 0x0 0x0>;
+
 		spi-max-frequency = <52000000>;
 		spi-tx-bus-width = <4>;
 		spi-rx-bus-width = <4>;