[BSP] Add BOARD_STM32F429_APPOLO option.

bsp/stm32f429-apollo/KConfig

@@ -15,6 +15,11 @@ config $PKGS_DIR
     option env="PKGS_ROOT"
     default "packages"
 
+config BOARD_STM32F429_APPOLO
+    bool 
+    select ARCH_ARM_CORTEX_M4
+    default y
+
 source "$RTT_DIR/KConfig"
 source "$PKGS_DIR/KConfig"