♻️ Refactor STM32 ini files (#22377)

Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>

buildroot/share/PlatformIO/boards/marlin_STEVAL_STM32F401VE.json

@@ -2,7 +2,7 @@
   "build": {
     "core": "stm32",
     "cpu": "cortex-m4",
-    "extra_flags": "-DSTM32F401xx",
+    "extra_flags": "-DSTM32F401xx -DARDUINO_STEVAL",
     "f_cpu": "84000000L",
     "hwids": [
       [

buildroot/share/PlatformIO/boards/marlin_blackSTM32F407VET6.json

@@ -2,7 +2,7 @@
   "build": {
     "core": "stm32",
     "cpu": "cortex-m4",
-    "extra_flags": "-DSTM32F407xx",
+    "extra_flags": "-DSTM32F407xx -DARDUINO_BLACK_F407VE",
     "f_cpu": "168000000L",
     "hwids": [
       [