arm: dts: enable MTK SPI NOR controller driver

1. Enable MTK SPI NOR controller driver on mt7622 & mt7629.
2. Enable quad mode for read and single mode for write.

diff --git a/arch/arm/dts/mt7629.dtsi b/arch/arm/dts/mt7629.dtsi
index 6850e00..0539426 100644
--- a/arch/arm/dts/mt7629.dtsi
+++ b/arch/arm/dts/mt7629.dtsi
@@ -223,6 +223,17 @@
 		#size-cells = <0>;
 	};
 
+	snor: snor@11014000 {
+		compatible = "mediatek,mtk-snor";
+		reg = <0x11014000 0x1000>;
+		clocks = <&pericfg CLK_PERI_FLASH_PD>,
+			 <&topckgen CLK_TOP_FLASH_SEL>;
+		clock-names = "spi", "sf";
+		status = "disabled";
+		#address-cells = <1>;
+		#size-cells = <0>;
+	};
+
 	ssusbsys: ssusbsys@1a000000 {
 		compatible = "mediatek,mt7629-ssusbsys", "syscon";
 		reg = <0x1a000000 0x1000>;