[BSP][STM32] 增加RT_USING_CPU_FFS配置选项
[BSP][STM32] 增加RT_USING_CPU_FFS配置选项

kconfig中增加RT_USING_CPU_FFS配置选项，并且默认开启
weiyuliang/rt-thread,armink/rt-thread,gbcwbz/rt-thread,weiyuliang/rt-thread,geniusgogo/rt-thread,hezlog/rt-thread,gbcwbz/rt-thread,nongxiaoming/rt-thread,nongxiaoming/rt-thread,weiyuliang/rt-thread,RT-Thread/rt-thread,RT-Thread/rt-thread,hezlog/rt-thread,FlyLu/rt-thread,FlyLu/rt-thread,nongxiaoming/rt-thread,weiyuliang/rt-thread,geniusgogo/rt-thread,FlyLu/rt-thread,RT-Thread/rt-thread,ArdaFu/rt-thread,ArdaFu/rt-thread,RT-Thread/rt-thread,weety/rt-thread,weiyuliang/rt-thread,armink/rt-thread,FlyLu/rt-thread,hezlog/rt-thread,armink/rt-thread,gbcwbz/rt-thread,nongxiaoming/rt-thread,weiyuliang/rt-thread,hezlog/rt-thread,geniusgogo/rt-thread,weety/rt-thread,armink/rt-thread,FlyLu/rt-thread,FlyLu/rt-thread,gbcwbz/rt-thread,armink/rt-thread,armink/rt-thread,weety/rt-thread,weety/rt-thread,ArdaFu/rt-thread,hezlog/rt-thread,FlyLu/rt-thread,RT-Thread/rt-thread,weety/rt-thread,weety/rt-thread,armink/rt-thread,ArdaFu/rt-thread,nongxiaoming/rt-thread,geniusgogo/rt-thread,weety/rt-thread,geniusgogo/rt-thread,gbcwbz/rt-thread,gbcwbz/rt-thread,geniusgogo/rt-thread,RT-Thread/rt-thread,nongxiaoming/rt-thread,ArdaFu/rt-thread,ArdaFu/rt-thread,gbcwbz/rt-thread,geniusgogo/rt-thread,ArdaFu/rt-thread,hezlog/rt-thread,nongxiaoming/rt-thread,hezlog/rt-thread,RT-Thread/rt-thread,weiyuliang/rt-thread