unoq: modify prescalers for 16bits timers to achieve low frequency PWM signals

timer1 and timer8 are 16bits timers instead of being 32bits as all other timers.In UNO Q overlay, prescaler is set to 4, so it means which is not possible to achieve 50Hz PWM signal frequency on related pins. This frequence is used to control RC Servo motors. By changing to 63, it is now possible to achieve 50Hz, maintaining unchanged 500Hz, used by default by analogWrite. At 500Hz is still possible to use 12bits resolution. Maximum frequency available is 1.25MHz with only 50% duty option.

Author: gbr1

variants/arduino_uno_q_stm32u585xx/arduino_uno_q_stm32u585xx.overlay

@@ -97,7 +97,7 @@
 /* Enable PWM timers */
 &timers1 {
 	status = "okay";
-	st,prescaler = <4>;
+	st,prescaler = <63>;
 
 	pwm1: pwm {
 		status = "okay";
@@ -160,7 +160,7 @@
 /* Currently only the pins marked with ~ on the pin headers are enabled */
 &timers8 {
 	status = "okay";
-	st,prescaler = <4>;
+	st,prescaler = <63>;
 
 	pwm8: pwm {
 		status = "okay";