MIPS: ls1bdev: fix a compile error

rt_hw_fpu_init() is defined in mips_fpu.h,
in board.c refered it without including mips_fpu.h.

Signed-off-by: duhuanpeng <548708880@qq.com>

bsp/ls1bdev/drivers/board.c

@@ -16,6 +16,7 @@
 
 #include <rtthread.h>
 #include <rthw.h>
+#include <mips_fpu.h>
 
 #include "board.h"
 #include "uart.h"