drm/mgag200: Fix driver_load error handling

mgag200_driver_load's error path just calls the drm driver's
driver_unload op. It isn't safe to call this because it doesn't handle
things well if driver_load fails somewhere mid way.

Replace the call to mgag200_driver_unload with a more finegrained
error handling path.

Link: http://lkml.kernel.org/r/[e-mail]
Reported-by: Ingo Molnar <[e-mail]>
Cc: Daniel Vetter <[e-mail]>
Cc: Dave Airlie <[e-mail]>
Cc: David Airlie <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Sudip Mukherjee <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: dri-devel <[e-mail]>
Signed-off-by: Archit Taneja <[e-mail]>
Signed-off-by: Dave Airlie <[e-mail]>

drivers/gpu/drm/mgag200/mgag200_main.c

···
 	}
 	r = mgag200_mm_init(mdev);
 	if (r)
-		goto out;
+		goto err_mm;
 
 	drm_mode_config_init(dev);
 	dev->mode_config.funcs = (void *)&mga_mode_funcs;
···
 	r = mgag200_modeset_init(mdev);
 	if (r) {
 		dev_err(&dev->pdev->dev, "Fatal error during modeset init: %d\n", r);
-		goto out;
+		goto err_modeset;
 	}
 
 	/* Make small buffers to store a hardware cursor (double buffered icon updates) */
···
 					  &mdev->cursor.pixels_1);
 	mgag200_bo_create(dev, roundup(48*64, PAGE_SIZE), 0, 0,
 					  &mdev->cursor.pixels_2);
-	if (!mdev->cursor.pixels_2 || !mdev->cursor.pixels_1)
-		goto cursor_nospace;
-	mdev->cursor.pixels_current = mdev->cursor.pixels_1;
-	mdev->cursor.pixels_prev = mdev->cursor.pixels_2;
-	goto cursor_done;
- cursor_nospace:
-	mdev->cursor.pixels_1 = NULL;
-	mdev->cursor.pixels_2 = NULL;
-	dev_warn(&dev->pdev->dev, "Could not allocate space for cursors. Not doing hardware cursors.\n");
- cursor_done:
+	if (!mdev->cursor.pixels_2 || !mdev->cursor.pixels_1) {
+		mdev->cursor.pixels_1 = NULL;
+		mdev->cursor.pixels_2 = NULL;
+		dev_warn(&dev->pdev->dev,
+			"Could not allocate space for cursors. Not doing hardware cursors.\n");
+	} else {
+		mdev->cursor.pixels_current = mdev->cursor.pixels_1;
+		mdev->cursor.pixels_prev = mdev->cursor.pixels_2;
+	}
 
-out:
-	if (r)
-		mgag200_driver_unload(dev);
+	return 0;
+
+err_modeset:
+	drm_mode_config_cleanup(dev);
+	mgag200_mm_fini(mdev);
+err_mm:
+	dev->dev_private = NULL;
+
 	return r;
 }