ixgbe: Make all unchanging ops structures const

The source for the ops structure contents are const, so make them
so. Copy them in place with structure assignments instead of memcpys.
Make the mbx_ops accessed by reference instead of making a copy of
the source structure. Update copyright date on the touched files.

Reported-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>