i40e: Add missing braces to i40e_dcb_need_reconfig()

Indentation mismatch spotted with Coverity.
Introduced in 4e3b35b0 ("i40e: add DCB and DCBNL support")

Signed-off-by: Dave Jones <davej@fedoraproject.org>
Signed-off-by: David S. Miller <davem@davemloft.net>