ath79: use ar934x-spi for ar933x as well

ar933x appears to have the same spi controller as ar934x but it's
not mentioned in datasheet at all. Use new spi driver instead to
gain more flash operating performance.

Signed-off-by: Chuanhong Guo <gch981213@gmail.com>

target/linux/ath79/dts/ar9330.dtsi

@@ -119,11 +119,10 @@
 		};
 
 		spi: spi@1f000000 {
-			compatible = "qca,ar7100-spi";
-			reg = <0x1f000000 0x10>;
+			compatible = "qca,ar934x-spi";
+			reg = <0x1f000000 0x1c>;
 
 			clocks = <&pll ATH79_CLK_AHB>;
-			clock-names = "ahb";
 
 			#address-cells = <1>;
 			#size-cells = <0>;