drm/appletbdrm: Fix ref-counting on dmadev

Remove the put_device() call on dmadev. The driver sets the field
without getting a reference, so it shouldn't put a reference either.
The dmadev field points to the regular USB device for which DRM
maintains a reference internally. Hence dmadev will not become dangling
during the DRM device's lifetime.

Signed-off-by: Thomas Zimmermann <[email protected]>
Fixes: 0670c2f ("drm/tiny: add driver for Apple Touch Bars in x86 Macs")
Cc: Aditya Garg <[email protected]>
Cc: Aun-Ali Zaidi <[email protected]>
Cc: [email protected]
Acked-by: Aditya Garg <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

Author: Thomas Zimmermann

drivers/gpu/drm/tiny/appletbdrm.c

@@ -805,7 +805,6 @@ static void appletbdrm_disconnect(struct usb_interface *intf)
 	struct appletbdrm_device *adev = usb_get_intfdata(intf);
 	struct drm_device *drm = &adev->drm;
 
-	put_device(adev->dmadev);
 	drm_dev_unplug(drm);
 	drm_atomic_helper_shutdown(drm);
 }