quoted

+               spi: spi at 1100a000 {
+                       compatible = "mediatek,mt8173-spi";
+                       #address-cells = <1>;
+                       #size-cells = <0>;
+                       reg = <0 0x1100a000 0 0x1000>;
+                       interrupts = <GIC_SPI 110 IRQ_TYPE_LEVEL_LOW>;
+                       clocks = <&topckgen CLK_TOP_SPI_SEL>, <&topckgen CLK_TOP_SYSPLL3_D2>;
+                       clock-names = "spi-clk", "parent-clk";
+                       pinctrl-names = "default";
+                       pinctrl-0 = <&spi_pins_a>;
+                       mediatek,pad-select = <0>;

The pinctl and pad-select fields are board specific.
Please move to mt8173-evb.dtsi, along with status = "okay";

OK, I will fix it.