[NETFILTER]: PPTP helper: fixup gre_keymap_lookup() return type

GRE keys are 16-bit wide.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed