浮点经常会用到，所以默认使用硬浮点。

    a. Libc改用官方版本（工具链附带版本）；
    b. 去除未使用文件；

[2] 基于AE210P EVB板；
[3] 详细信息参阅bsp/AE210P/readme文件夹；
    《Andes工程创建和调试》文档；等。

modify：     ../../libcpu/risc-v/e310/stack.c
	rmove unused macro definition
modify：     ../../src/idle.c
	Return to the original version

	add file that forget to submit before
	auto change timer mtimercmp register on the base of RT_TICK_PER_SECOND in rtconfig.h
	no flashing led
new file：   ../../src/idle.c
	recover old file

	save mie into stack
msh  running normaly

	save sp to old thread
	clear rt_thread_switch_interrupt_flag
always enable interrupt after rt_hw_context_switch
judeg the type of interrupt in trap_entry, then call handler(Machine timer interrupt of Machine external interrupt)

	enable interrupt after return form rt_hw_context_switch

fix open timer intrrupt

	it will lead to interrupt again in interrupt

modified:   ../../libcpu/risc-v/e310/context_gcc.S
	change  ret to mret and switch to new task with mepc

committed by FH.

committed by FH.

FH8620 BSP
Copyright (c) 2016 Shanghai Fullhan Microelectronics Co., Ltd.
All rights reserved

code cleanup.