AP_HAL_ChibiOS: reversible DShot fix

Co-authored-by: Andy Piper <github@andypiper.com>

libraries/AP_HAL_ChibiOS/RCOutput.cpp

@@ -1404,7 +1404,7 @@ void RCOutput::dshot_send(pwm_group &group, uint32_t time_out_us)
             pwm = constrain_int16(pwm, 1000, 2000);
             uint16_t value = MIN(2 * (pwm - 1000), 1999);
 
-            if (chan_mask & (_reversible_mask>>chan_offset)) {
+            if ((chan_mask & _reversible_mask) != 0) {
                 // this is a DShot-3D output, map so that 1500 PWM is zero throttle reversed
                 if (value < 1000) {
                     value = 1999 - value;