Fix lf

[components][lwip]添加 LWIP 硬件校验和选项，修改 STM32 系列和 rt1052 系列以太网驱动，支持硬件校验和

[components] 添加 RT_USING_ALARM 选项

[bsp/stm32f411]add pwm driver

[components/shell] shell will not work if ch is none zero as random value in stack

The serial getchar will only modify the LSB of ch, the MSB 3 bytes
will be unchanged as the random value on stack, so if MSB 3 bytes
not zero, the value got is wrong.

fix stm32767 lf

[bsp][stm32] modify sdram configuration

[BSP][i.MXRT]Add NXP i.MXRT1021-EVK BSP Support

[bsp/es32f0654] add pwm drivers

Delete the unused '--keep' link flag when used RT_USED marco.

[BSP][K210]Add LCD Camera driver

[ci] rm auto test stage

Signed-off-by: zyh <lymz@foxmail.com>

Signed-off-by: NMurphyZhao <d2014zjt@163.com>

[finsh] change return type of finsh_getchar from ch to int

[BSP]添加两个STM32的BSP

我们学生一般都会用体积比较小的最小系统，也就是网上热卖的STM32F103C8T6最小系统，所以先做出这个最小系统的BSP，方便大家直接使用到自己的项目当中，也方便那些没有开发板的人用这个最小系统学习RTT

因为刚入手RT-Thread的时候就想找这个正点原子战舰V3开发板的BSP，结果没找到，一开始就制作BSP门槛相对高了，特此增加了正点原子的战舰V3开发板的BSP（STM32F103ZET6），方便所有和我用这款开发板的人快速入门RTT

finsh_getchar invokes getchar, who's return type is int, and return value may < 0, which means error occurred or EOF.
finsh should handle that situation properly, and inform user about the error.