fix(battery_simulator): disable battery sim only if SIM_BAT_DRAIN strictly < 0

ROMFS/px4fmu_common/init.d-posix/rcS

@@ -249,7 +249,7 @@ fi
 
 load_mon start
 
-if param greater SIM_BAT_DRAIN 0
+if param greater SIM_BAT_DRAIN 0 || param compare SIM_BAT_DRAIN 0
 then
 	battery_simulator start
 fi

src/modules/simulation/battery_simulator/battery_simulator_params.yaml

@@ -6,7 +6,7 @@ parameters:
       description:
         short: Simulator Battery drain interval
         long: |-
-          Set <= 0 to entirely disable the battery simulator.
+          Set to -1 to entirely disable the battery simulator.
           This is useful when the battery is simulated externally and interfaced with PX4, for example through MAVLink.
       type: float
       default: 60