keep cortext m4 settings for 917 soc

Author: jmartinez-silabs

third_party/silabs/silabs_arm.gni

@@ -14,7 +14,13 @@
 
 import("silabs_board.gni")
 
-if (silabs_family == "efr32mg24" || silabs_family == "mgm24") {
+if (silabs_family == "SiWx917-common") {
+  arm_arch = "armv7e-m"
+  arm_abi = "aapcs"
+  arm_cpu = "cortex-m4"
+  arm_float_abi = "softfp"
+  arm_fpu = "fpv4-sp-d16"
+} else if (silabs_family == "efr32mg24" || silabs_family == "mgm24") {
   arm_arch = "armv8-m.main+dsp"
   arm_abi = "aapcs"
   arm_cpu = "cortex-m33"