prevent double-precision promotion where its not required

apps/systemlib/pid/pid.c

@@ -155,8 +155,8 @@ __EXPORT float pid_calculate(PID_t *pid, float sp, float val, float val_dot, flo
 	// Calculate the error integral and check for saturation
 	i = pid->integral + (error * dt);
 
-	if (fabs((error * pid->kp) + (i * pid->ki) + (d * pid->kd)) > pid->limit ||
-	    fabs(i) > pid->intmax) {
+	if (fabsf((error * pid->kp) + (i * pid->ki) + (d * pid->kd)) > pid->limit ||
+	    fabsf(i) > pid->intmax) {
 		i = pid->integral;		// If saturated then do not update integral value
 		pid->saturated = 1;