i40e: Fix missing rtnl locking when setting up pf switch
A recent change that made i40e use new udp_tunnel infrastructure
uses a method that expects to be called under rtnl lock.
However, not all codepaths do the lock prior to calling
i40e_setup_pf_switch.
Fix that by adding additional rtnl locking and unlocking.
Fixes: 40a98cb6f01f ("i40e: convert to new udp_tunnel infrastructure") Signed-off-by: Jan Sokolowski <jan.sokolowski@intel.com> Signed-off-by: Mateusz Palczewski <mateusz.palczewski@intel.com> Tested-by: Tony Brelinski <tonyx.brelinski@intel.com> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>