"vif" is assigned twice.  We can remove the first one.

This silences a Smatch warning that "ctx" could be one step past the
end of the priv->contexts[] array.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Reviewed-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>