simplify board API, adding stm32f3 discovery

- remove board header since it is not used

examples/device/cdc_msc_hid/ses/lpc175x_6x/lpc175x_6x.emProject

@@ -19,7 +19,7 @@
       arm_target_device_name="LPC1769"
       arm_target_interface_type="SWD"
       build_treat_warnings_as_errors="Yes"
-      c_preprocessor_definitions="LPC175x_6x;__LPC1700_FAMILY;__LPC176x_SUBFAMILY;ARM_MATH_CM3;FLASH_PLACEMENT=1;CORE_M3;BOARD_LPCXPRESSO1769;CFG_TUSB_MCU=OPT_MCU_LPC175X_6X"
+      c_preprocessor_definitions="LPC175x_6x;__LPC1700_FAMILY;__LPC176x_SUBFAMILY;ARM_MATH_CM3;FLASH_PLACEMENT=1;CORE_M3;CFG_TUSB_MCU=OPT_MCU_LPC175X_6X"
       c_user_include_directories="../../src;$(rootDir)/hw;$(rootDir)/hw/mcu/nxp/lpcopen/lpc_chip_175x_6x/inc;$(rootDir)/src"
       debug_register_definition_file="LPC176x5x_Registers.xml"
       debug_target_connection="J-Link"
@@ -107,6 +107,9 @@
       filter="*.c;*.h"
       path="../../../../../lib/segger_rtt"
       recurse="No" />
+    <configuration
+      Name="LPCXpresso 1769"
+      c_preprocessor_definitions="BOARD_LPCXPRESSO1769" />
   </project>
   <configuration Name="LPCXpresso 1769" />
 </solution>