update msp430 make build

Author: hathach

examples/build_system/make/cpu/msp430.mk

@@ -0,0 +1,8 @@
+ifeq ($(TOOLCHAIN),gcc)
+  # nothing to add
+else ifeq ($(TOOLCHAIN),iar)
+  # nothing to add
+endif
+
+# For freeRTOS port source
+FREERTOS_PORTABLE_SRC ?= $(FREERTOS_PORTABLE_PATH)/GCC_MSP430F449

hw/bsp/msp430/boards/msp_exp430f5529lp/board.mk

@@ -0,0 +1,4 @@
+CFLAGS += \
+  -D__MSP430F5529__ \
+
+LD_FILE = ${SDK_DIR}/msp430f5529.ld

hw/bsp/msp430/family.mk

@@ -4,14 +4,13 @@ SKIP_NANOLIB = 1
 
 SDK_DIR = hw/mcu/ti/msp430/msp430-gcc-support-files/include
 
+include $(TOP)/$(BOARD_PATH)/board.mk
+
 CFLAGS += \
-  -D__MSP430F5529__ \
   -DCFG_TUSB_MCU=OPT_MCU_MSP430x5xx \
 	-DCFG_EXAMPLE_MSC_READONLY \
 	-DCFG_TUD_ENDPOINT0_SIZE=8
 
-# All source paths should be relative to the top level.
-LD_FILE = ${SDK_DIR}/msp430f5529.ld
 LDFLAGS += -L${TOP}/${SDK_DIR}
 
 SRC_C += src/portable/ti/msp430x5xx/dcd_msp430x5xx.c