[bsp][stm32] optimize Kconfig file

bsp/stm32/stm32f091-st-nucleo/board/Kconfig

@@ -9,7 +9,7 @@ menu "Onboard Peripheral Drivers"
 
     config BSP_USING_USB_TO_USART
         bool "Enable USB TO USART (uart2)"
-	select BSP_USING_UART
+        select BSP_USING_UART
         select BSP_USING_UART2
         default y
 

bsp/stm32/stm32l475-atk-pandora/board/Kconfig

@@ -51,7 +51,7 @@ menu "On-chip Peripheral Drivers"
                 bool "Enable UART1 RX DMA"
                 depends on BSP_USING_UART1 && RT_SERIAL_USING_DMA
                 default n
-                
+
             config BSP_USING_UART2
                 bool "Enable UART2"
                 default n