omnibus: add support for Hobbywing XRotor F4 G2

It has an ICM-20602 IMU

ROMFS/px4fmu_common/init.d/rc.sensors

@@ -297,7 +297,12 @@ fi
 
 if ver hwcmp OMNIBUS_F4SD
 then
-	mpu6000 -R 12 -s start
+	if mpu6000 -R 12 -s start
+	then
+	else
+		# some boards such as the Hobbywing XRotor F4 G2 use the ICM-20602
+		mpu6000 -R 12 -T 20602 -s start
+	fi
 
 	# Possible external compasses
 	hmc5883 -X start

src/drivers/boards/omnibus-f4sd/board_config.h

@@ -172,6 +172,7 @@
 // One device per bus
 #define PX4_SPI_BUS_SENSORS         1
 #define PX4_SPIDEV_MPU              1
+#define PX4_SPIDEV_ICM_20602        1
 #define PX4_SPIDEV_BARO_BUS         3
 #define PX4_SPIDEV_BARO             1