px4io firmware: Allow actuator update rates down to 25Hz. This allows to

set the same update rate on PX4IO as on many commercial RC systems (e.g.
Spektrum, which works at 45Hz servo update rate).

src/modules/px4iofirmware/registers.c

@@ -543,8 +543,8 @@ registers_set_one(uint8_t page, uint8_t offset, uint16_t value)
 			break;
 
 		case PX4IO_P_SETUP_PWM_DEFAULTRATE:
-			if (value < 50) {
-				value = 50;
+			if (value < 25) {
+				value = 25;
 			}
 			if (value > 400) {
 				value = 400;
@@ -553,8 +553,8 @@ registers_set_one(uint8_t page, uint8_t offset, uint16_t value)
 			break;
 
 		case PX4IO_P_SETUP_PWM_ALTRATE:
-			if (value < 50) {
-				value = 50;
+			if (value < 25) {
+				value = 25;
 			}
 			if (value > 400) {
 				value = 400;