[][dts: mt7986: update SPIM's max frequency to 52MHz]

[Description]
Change SPIM's max frequency to 52MHz

[Release-log]
N/A

Change-Id: I5897deaa868e60eb81c74cef79f6a52148ee8a81
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/5396035
diff --git a/target/linux/mediatek/files-5.4/arch/arm64/boot/dts/mediatek/mt7986a-2500wan-spim-nor-rfb.dts b/target/linux/mediatek/files-5.4/arch/arm64/boot/dts/mediatek/mt7986a-2500wan-spim-nor-rfb.dts
index 03df637..c1f22d1 100644
--- a/target/linux/mediatek/files-5.4/arch/arm64/boot/dts/mediatek/mt7986a-2500wan-spim-nor-rfb.dts
+++ b/target/linux/mediatek/files-5.4/arch/arm64/boot/dts/mediatek/mt7986a-2500wan-spim-nor-rfb.dts
@@ -192,7 +192,7 @@
 		#size-cells = <1>;
 		compatible = "jedec,spi-nor";
 		reg = <0>;
-		spi-max-frequency = <20000000>;
+		spi-max-frequency = <52000000>;
 		spi-tx-buswidth = <4>;
 		spi-rx-buswidth = <4>;
 	};