igbvf: fix the bug when initializing the igbvf

Maybe it's a typo, but it cause that igbvf can't be initialized successfully.
Set perm_addr value using valid dev_addr, although which is equal to hw.mac.addr.

Signed-off-by: Samuel Liao <samuelliao@tencent.com>
Signed-off-by: Shan Wei <davidshan@tencent.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>