These functions are only used in ixgbe_x550.c.

Fixes a warning when compiling with -Wmissing-prototypes
Reported-by: NKrishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: NEmil Tantilov <emil.s.tantilov@intel.com>
Tested-by: NAndrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>