myri10ge: fix incorrect use of ntohs()

1b4c44e6 incorrectly used
ntohs() rather than htons() in myri10ge_vlan_rx().

Thanks to Fengguang Wu, Yuanhan Liu's kernel-build tester
for pointing out this bug.

Signed-off-by: Andrew Gallatin <gallatin@myri.com>
Signed-off-by: David S. Miller <davem@davemloft.net>