HAL_Linux: use MODE_3 for MPU9250

this fixes the MS5611 (probably due to idle state?)

libraries/AP_HAL_Linux/SPIDriver.cpp

@@ -23,7 +23,7 @@ extern const AP_HAL::HAL& hal;
 LinuxSPIDeviceDriver LinuxSPIDeviceManager::_device[LINUX_SPI_DEVICE_NUM_DEVICES] = {
     LinuxSPIDeviceDriver(1, LINUX_SPI_DEVICE_MS5611,  SPI_MODE_3, 8,   7,  6*MHZ, 6*MHZ),
     LinuxSPIDeviceDriver(1, LINUX_SPI_DEVICE_MPU6000, SPI_MODE_3, 8, 113,  500*1000, 20*MHZ),
-    LinuxSPIDeviceDriver(1, LINUX_SPI_DEVICE_MPU9250, SPI_MODE_0, 8,  49,  6*MHZ, 6*MHZ),
+    LinuxSPIDeviceDriver(1, LINUX_SPI_DEVICE_MPU9250, SPI_MODE_3, 8,  49,  6*MHZ, 20*MHZ),
     LinuxSPIDeviceDriver(0, LINUX_SPI_DEVICE_LSM9DS0, SPI_MODE_0, 8,   5,  6*MHZ, 6*MHZ),
     LinuxSPIDeviceDriver(1, LINUX_SPI_DEVICE_FRAM,    SPI_MODE_0, 8,  44,  6*MHZ, 6*MHZ)
 };