Intel Wired LAN drivers: Use static const

Based on work by Joe Perches <joe@perches.com>

Using static const to decrease data and overall object size.

CC: Joe Perches <joe@perches.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Tested-by: Emil Tantilov <emil.s.tantilov@intel.com>