Better initial config for Phantom

ROMFS/px4fmu_common/init.d/3031_phantom

@@ -30,6 +30,9 @@ then
 	param set FW_RR_P 0.08
 	param set FW_R_LIM 50
 	param set FW_R_RMAX 0
+	# Bottom of bay and nominal zero-pitch attitude differ
+	# the payload bay is pitched up about 7 degrees
+	param set SENS_BOARD_Y_OFF 7.0
 fi
 
 set MIXER phantom