ixgbe: store permanent address before initializing Rx addresses

We were reading the address after it had been initialized and this results
in the permanent address on the system being changed.  This change corrects
that by storing the address before we re-initialize it.

Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Stephen Ko <stephen.s.ko@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>