用全局空间换栈空间，当多个任务需要使用sfud时，可以节省内存
例如多个任务需要使用文件系统，任务栈可以减少

fix some bug when stack grows upward

添加cpu复位函数

[Kernel] Fix the thread->sp data type issue.

 [bsp][stm32 hal drv_gpio] add  more settings for "GPIO_InitStruct.Pull" 

完善 hwtimer 测试例程，修改 readme 显示错误

RT_WEAK void rt_hw_cpu_reset(void)

修复I2C和RTC中的粗心BUG

[bsp][stm32] optimize scons --dist function

Fix the value width issue under 32/64 bit arch.

[bsp][stm32 hal drv_gpio]If there is no pull-up or pull-down outside, there will be problems with just setting "GPIO_InitStruct.Pull = GPIO_NOPULL".

更新

137行多了()

I2C2_BUS_CONFIG改为I2C3_BUS_CONFIG

[components][utilities] 增加 utest（单元测试框架）

Update at_socket.c

修改socket读取遗留数据逻辑

fix_smp

2 RTM_EXPORT(rt_cpus_lock_status_restore)
3 sync ARCH_CPU_STACK_GROWS_UPWARD in _rt_scheduler_stack_check()

[bsp][lpc54114] 修复drv_gpio.c drv_romfs.c驱动未被默认编译的问题.

修复spi驱动中spi_config一个bug

add lwp support

修改cpu目录名及相关修改

[bsp][stm32] add more drivers for stm32 bsp