HID: debug: check length before copy_to_user()

HID: debug: check length before copy_to_user()

If our length is greater than the size of the buffer, we
overflow the buffer

Cc: stable@vger.kernel.org
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
(cherry picked from commit 717adfdaf14704fd3ec7fa2c04520c0723247eac)
Orabug: 29128165
CVE: CVE-2018-9516
Signed-off-by: Somasundaram Krishnasamy <somasundaram.krishnasamy@oracle.com>
Reviewed-by: John.Donnelly <John.p.donnelly@oracle.com>
Signed-off-by: Brian Maly <brian.maly@oracle.com>