hwdef: add BMP581 as Barometer option on Pixhawk6X

Author: peterbarker

libraries/AP_HAL_ChibiOS/hwdef/Pixhawk6X/hwdef.dat

@@ -285,6 +285,10 @@ PI5 TIM8_CH1 TIM8 RCININT PULLDOWN LOW
 BARO BMP388 I2C:2:0x76
 BARO BMP388 I2C:0:0x77
 
+# barometers (Holybro 6X more recent versions)
+BARO BMP581 I2C:2:0x46
+BARO BMP581 I2C:0:0x46
+
 # barometers (CUAV 6X)
 BARO ICP201XX I2C:0:0x64
 BARO ICP201XX I2C:2:0x63