[RTduino][stm32l476-nucleo] correct D9 pwm3 channel number

bsp/stm32/stm32l476-st-nucleo/board/Kconfig

@@ -27,8 +27,8 @@ menu "Onboard Peripheral Drivers"
         select BSP_USING_PWM2_CH2
         select BSP_USING_PWM2_CH3
         select BSP_USING_PWM3
-        select BSP_USING_PWM3_CH0
         select BSP_USING_PWM3_CH1
+        select BSP_USING_PWM3_CH2
         select BSP_USING_PWM4
         select BSP_USING_PWM4_CH1
         select BSP_USING_PWM17
@@ -210,12 +210,12 @@ menu "On-chip Peripheral Drivers"
             bool "Enable timer3 output PWM"
             default n
             if BSP_USING_PWM3
-                config BSP_USING_PWM3_CH0
-                    bool "Enable PWM3 channel0"
-                    default n
                 config BSP_USING_PWM3_CH1
                     bool "Enable PWM3 channel1"
                     default n
+                config BSP_USING_PWM3_CH2
+                    bool "Enable PWM3 channel2"
+                    default n
             endif
 
         menuconfig BSP_USING_PWM4