Move FAST_PWM_FAN code to HALs (#13491)

Marlin/src/HAL/HAL_LPC1768/HAL.h

@@ -157,3 +157,19 @@ void HAL_idletask(void);
 
 #define PLATFORM_M997_SUPPORT
 void flashFirmware(int16_t value);
+
+/**
+ * set_pwm_frequency
+ *  Set the frequency of the timer corresponding to the provided pin
+ *  All Hardware PWM pins run at the same frequency and all
+ *  Software PWM pins run at the same frequency
+ */
+void set_pwm_frequency(const pin_t pin, int f_desired);
+
+/**
+ * set_pwm_duty
+ *  Set the PWM duty cycle of the provided pin to the provided value
+ *  Optionally allows inverting the duty cycle [default = false]
+ *  Optionally allows changing the maximum size of the provided value to enable finer PWM duty control [default = 255]
+ */
+void set_pwm_duty(const pin_t pin, const uint16_t v, const uint16_t v_size=255, const bool invert=false);