Removing alternative io timer rate for CF2

ROMFS/px4fmu_common/init.d/4900_crazyflie

@@ -38,4 +38,5 @@ fi
 set PWM_MIN none
 set PWM_MAX none
 set PWM_DISARMED none
-set PWM_RATE 500
+# Will run the motors at 328.125 kHz (recommended)
+set PWM_RATE 3921

src/drivers/boards/crazyflie/board_config.h

@@ -173,10 +173,6 @@
 #define PWM_DEFAULT_MAX 255
 #define PWM_LOWEST_MAX 255
 
-/* Override the io timers to update at 328.125 kHz (recommended) */
-
-#define PX4_IO_TIMER_ALTERNATE_RATE     255
-
 
 /* High-resolution timer */
 #define HRT_TIMER		8	/* use timer8 for the HRT */

src/drivers/stm32/drv_io_timer.c

@@ -379,17 +379,9 @@ static int allocate_channel(unsigned channel, io_timer_channel_mode_t mode)
 
 static int timer_set_rate(unsigned timer, unsigned rate)
 {
-#if defined(PX4_IO_TIMER_ALTERNATE_RATE)
-
-	/* Override the rate to a constant that could be provided by the board */
-
-	rARR(timer) = PX4_IO_TIMER_ALTERNATE_RATE;
-#else
 
 	/* configure the timer to update at the desired rate */
-
 	rARR(timer) = 1000000 / rate;
-#endif
 
 	/* generate an update event; reloads the counter and all registers */
 	rEGR(timer) = GTIM_EGR_UG;