boards:Using pwm on nuttx bp (Button and LED changes)

[samudiio]

We will use the PB0 pin and the Timer 3 Channel 3 to generate this pulse

./tools/configure.sh stm32f411-minimum:pwm

make menuconfig

->System Type -> STM32 Peripheral Support -> TIM3[] ->System Type -> Timer configuration -> TIM3 PWM [] ->System Type -> Timer configuration -> TIM3 PWM Output Channel (3) -> Device Drivers -> Timer Driver Support -> PWM Driver Support [*] -> Application Configuration -> Examples -> Pulse width modulation (PWM) example (/dev/pwm0) PWM device path (100) Default PWM frequency (5) Default PWM duration (50) Default PWM duty percentage

make -j

openocd -f interface/stlink.cfg -f target/stm32f4x.cfg -c init -c "reset halt" -c "flash write_image erase nuttx.bin 0x08000000"

[xiaoxiang781216]

@samudiio please squash the last three patch to the related change.

[xiaoxiang781216]

@samudiio do you want to continue this PR or close directly?