boards: pixhawk 2 cube skip starting low quality l3gd20 gyro to save memory and cpu

- free memory is getting tight on these older boards (depending on
configuratoin) and the pixhawk 2 cube still has 2 other superior IMUs, so this is just
dropping dead weight

boards/px4/fmu-v2/init/rc.board_sensors

@@ -1,6 +1,6 @@
 #!/bin/sh
 #
-# PX4 FMUv2 specific board sensors init
+# board specific sensors init
 #------------------------------------------------------------------------------
 
 rgbled start -I
@@ -65,12 +65,6 @@ then
 	# sensor heating is available, but we disable it for now
 	param set-default SENS_EN_THERMAL 0
 
-	# l3gd20 (external/isolated SPI4)
-	l3gd20 -s -b 4 -R 4 start
-
-	# lsm303d (external/isolated SPI4)
-	lsm303d -s -b 4 -R 6 start
-
 	# ms5611 (external/isolated SPI4)
 	ms5611 -s -b 4 start
 
@@ -89,6 +83,13 @@ then
 		mpu9250 -s -b 1 start
 	fi
 
+	# l3gd20 (external/isolated SPI4)
+	# low quality sensor disabled by default to save memory
+	#l3gd20 -s -b 4 -R 4 start
+
+	# lsm303d (external/isolated SPI4)
+	lsm303d -s -b 4 -R 6 start
+
 else
 	# $BOARD_FMUV3 = 0 -> FMUv2
 

boards/px4/fmu-v3/init/rc.board_defaults

@@ -5,3 +5,4 @@
 
 param set-default BAT1_V_DIV 10.177939394
 param set-default BAT1_A_PER_V 15.391030303
+

boards/px4/fmu-v3/init/rc.board_sensors

@@ -1,6 +1,6 @@
 #!/bin/sh
 #
-# PX4 FMUv3 specific board sensors init
+# board specific sensors init
 #------------------------------------------------------------------------------
 
 rgbled start -I
@@ -65,12 +65,6 @@ then
 	# sensor heating is available, but we disable it for now
 	param set-default SENS_EN_THERMAL 0
 
-	# l3gd20 (external/isolated SPI4)
-	l3gd20 -s -b 4 -R 4 start
-
-	# lsm303d (external/isolated SPI4)
-	lsm303d -s -b 4 -R 6 start
-
 	# ms5611 (external/isolated SPI4)
 	ms5611 -s -b 4 start
 
@@ -89,6 +83,13 @@ then
 		mpu9250 -s -b 1 start
 	fi
 
+	# l3gd20 (external/isolated SPI4)
+	# low quality sensor disabled by default to save memory
+	#l3gd20 -s -b 4 -R 4 start
+
+	# lsm303d (external/isolated SPI4)
+	lsm303d -s -b 4 -R 6 start
+
 else
 	# $BOARD_FMUV3 = 0 -> FMUv2