If device_register() fails then call put_device().  See comment to
device_register.
Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
Cc: Maxim Levitsky <maximlevitsky@gmail.com>
Cc: Alex Dubov <oakad@yahoo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>