mediatek: mt7623: import patch to fix spi

mediatek: mt7623: import patch to fix spi

The patch fixes the fifo rx mode for the mt7623. It is already accepted
upstream for Linux Kernel 5.15.

To test the spi we can change the dts file to

&spi0 {
	pinctrl-names = "default";
	pinctrl-0 = <&spi0_pins_a>;
	status = "okay";
	spidev: spidev@0 {
		compatible = "linux,spidev";
		spi-max-frequency = <1000000>;
		reg = <0>;
	};
};

Afterwards we should see a spidev device under /dev/.
To test it we can further use spidev-test.

Signed-off-by: Nick Hainke <vincent@systemli.org>