i40e: make i40e_init_pf_fcoe to void

i40e_init_pf_fcoe() didn't return anything except 0, it prints enough
error info already, and no driver logic depends on the return value,
so this can be void.

Change-ID: Ie6afad849857d87a7064c42c3cce14c74c2f29d8
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>