drivers/net/ethernet: rid ethernet of no-prototype warnings

The W=1 builds showed a few files exporting functions
(non-static) that were not prototyped. What actually happened is
that there were prototypes, but the include file was forgotten in
the implementation file.

Add the include file and remove the warnings.

Fixed Warnings:
drivers/net/ethernet/cavium/liquidio/cn68xx_device.c:124:5: warning: no previous prototype for ‘lio_setup_cn68xx_octeon_device’ [-Wmissing-prototypes]
drivers/net/ethernet/cavium/liquidio/octeon_mem_ops.c:159:1: warning: no previous prototype for ‘octeon_pci_read_core_mem’ [-Wmissing-prototypes]
drivers/net/ethernet/cavium/liquidio/octeon_mem_ops.c:168:1: warning: no previous prototype for ‘octeon_pci_write_core_mem’ [-Wmissing-prototypes]
drivers/net/ethernet/cavium/liquidio/octeon_mem_ops.c:176:5: warning: no previous prototype for ‘octeon_read_device_mem64’ [-Wmissing-prototypes]
drivers/net/ethernet/cavium/liquidio/octeon_mem_ops.c:185:5: warning: no previous prototype for ‘octeon_read_device_mem32’ [-Wmissing-prototypes]
drivers/net/ethernet/cavium/liquidio/octeon_mem_ops.c:194:6: warning: no previous prototype for ‘octeon_write_device_mem32’ [-Wmissing-prototypes]
drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_dcb.c:453:6: warning: no previous prototype for ‘hclge_dcb_ops_set’ [-Wmissing-prototypes]

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>