F7: fix pwm clock
#ifdef STM32F7
#define SYS_CLOCK_FREQ_HZ 216000000
-#define PWM_CLOCK_FREQ_HZ 84000000
+#define PWM_CLOCK_FREQ_HZ 216000000
#define SPI_CLOCK_FREQ_HZ (SYS_CLOCK_FREQ_HZ / 4)
#define LOOPTIME LOOPTIME_8K
