IB/core: Fix dereference before check

Sparse complains about dereference before check. Fixing this by
moving the check before the dereference.

Fixes: 200298326b27 ('IB/core: Validate route when we init ah')
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
1 file changed