Make sure to check the number of endpoints to avoid dereferencing a
NULL-pointer should a malicious device lack endpoints.
Fixes: cf7776dc05 ("[PATCH] isdn4linux: Siemens Gigaset drivers -
direct USB connection")
Cc: stable <stable@vger.kernel.org> # 2.6.17
Cc: Hansjoerg Lipp <hjlipp@web.de>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>