drm/hyperv: Fix an error handling path in hyperv_vmbus_probe()

hyperv_setup_vram() calls vmbus_allocate_mmio(). This must be undone in
the error handling path of the probe, as already done in the remove
function.

Fixes: a0ab5ab ("drm/hyperv : Removing the restruction of VRAM allocation with PCI bar size")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/7dfa372af3e35fbb1d6f157183dfef2e4512d3be.1659297696.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Wei Liu <wei.liu@kernel.org>

drivers/gpu/drm/hyperv/hyperv_drm_drv.c

@@ -133,7 +133,6 @@ static int hyperv_vmbus_probe(struct hv_device *hdev,
 	}
 
 	ret = hyperv_setup_vram(hv, hdev);
-
 	if (ret)
 		goto err_vmbus_close;
 
@@ -150,18 +149,20 @@ static int hyperv_vmbus_probe(struct hv_device *hdev,
 
 	ret = hyperv_mode_config_init(hv);
 	if (ret)
-		goto err_vmbus_close;
+		goto err_free_mmio;
 
 	ret = drm_dev_register(dev, 0);
 	if (ret) {
 		drm_err(dev, "Failed to register drm driver.\n");
-		goto err_vmbus_close;
+		goto err_free_mmio;
 	}
 
 	drm_fbdev_generic_setup(dev, 0);
 
 	return 0;
 
+err_free_mmio:
+	vmbus_free_mmio(hv->mem->start, hv->fb_size);
 err_vmbus_close:
 	vmbus_close(hdev->channel);
 err_hv_set_drv_data: