mei: Fix error handling in mei_register

mei_register() fails to release the device reference in error paths
after device_initialize(). During normal device registration, the
reference is properly handled through mei_deregister() which calls
device_destroy(). However, in error handling paths (such as cdev_alloc
failure, cdev_add failure, etc.), missing put_device() calls cause
reference count leaks, preventing the device's release function
(mei_device_release) from being called and resulting in memory leaks
of mei_device.

Found by code review.

Cc: stable <stable@kernel.org>
Fixes: 7704e6be4e ("mei: hook mei_device on class device")
Signed-off-by: Ma Ke <make24@iscas.ac.cn>
Acked-by: Alexander Usyskin <alexander.usyskin@intel.com>
Link: https://patch.msgid.link/20251104020133.5017-1-make24@iscas.ac.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/main.c

@@ -1307,6 +1307,7 @@ int mei_register(struct mei_device *dev, struct device *parent)
 err_del_cdev:
 	cdev_del(dev->cdev);
 err:
+	put_device(&dev->dev);
 	mei_minor_free(minor);
 	return ret;
 }