[ci] remove unnecessary stm32 bsp

Author: BernardXiong

.travis.yml

@@ -74,9 +74,7 @@ env:
   - RTT_BSP='stm32f20x' RTT_TOOL_CHAIN='sourcery-arm' 
   - RTT_BSP='stm32f40x' RTT_TOOL_CHAIN='sourcery-arm' 
   - RTT_BSP='stm32f4xx-HAL' RTT_TOOL_CHAIN='sourcery-arm' 
-  - RTT_BSP='stm32f411-nucleo' RTT_TOOL_CHAIN='sourcery-arm' 
   - RTT_BSP='stm32f429-apollo' RTT_TOOL_CHAIN='sourcery-arm' 
-#  - RTT_BSP='stm32f429-armfly' RTT_TOOL_CHAIN='sourcery-arm' 
   - RTT_BSP='stm32f429-disco' RTT_TOOL_CHAIN='sourcery-arm' 
   - RTT_BSP='stm32l475-iot-disco' RTT_TOOL_CHAIN='sourcery-arm' 
   - RTT_BSP='stm32l476-nucleo' RTT_TOOL_CHAIN='sourcery-arm'