boards: arm: mec172xevb: Update SPI HW block properties

Reflect device tree field name.

Signed-off-by: Jose Alberto Meza <jose.a.meza.arellano@intel.com>
diff --git a/boards/arm/mec172xevb_assy6906/mec172xevb_assy6906.dts b/boards/arm/mec172xevb_assy6906/mec172xevb_assy6906.dts
index 20989a2..2e99980 100644
--- a/boards/arm/mec172xevb_assy6906/mec172xevb_assy6906.dts
+++ b/boards/arm/mec172xevb_assy6906/mec172xevb_assy6906.dts
@@ -210,8 +210,8 @@
 	status = "okay";
 	clock-frequency = <4000000>;
 	lines = <4>;
-	chip-select = <0>;
-	port-sel = <0>; /* Shared SPI */
+	chip_select = <0>;
+	port_sel = <0>; /* Shared SPI */
 
 	pinctrl-0 = < &shd_cs0_n_gpio055
 		      &shd_clk_gpio056