bus: mhi: core: Fix a NULL vs IS_ERR check in mhi_create_devices()

The mhi_alloc_device() function never returns NULL, it returns error
pointers.

Fixes: da1c4f85 ("bus: mhi: core: Add support for creating and destroying MHI devices")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200407093133.GM68494@mwandaSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/bus/mhi/core/main.c

@@ -294,7 +294,7 @@ void mhi_create_devices(struct mhi_controller *mhi_cntrl)
 		    !(mhi_chan->ee_mask & BIT(mhi_cntrl->ee)))
 			continue;
 		mhi_dev = mhi_alloc_device(mhi_cntrl);
-		if (!mhi_dev)
+		if (IS_ERR(mhi_dev))
 			return;
 
 		mhi_dev->dev_type = MHI_DEVICE_XFER;