af_packet: show host interface offload flags

af_packet: show host interface offload flags

Type: improvement

This patch implements support to show host interface offload
flags at the time of creation. It also shows host interface
offload flags at the time of calling given function through
'show hardware'.

Before:
  Host Interface Offload:
    creation time:
     rx checksum
     tx checksum
     tcp segmentation offload
     generic segemanttaion offload
    now:
     rx checksum
     tx checksum
     tcp segmentation offload
     generic segemanttaion offload

After changing the offloads on the veth using ethtool command ('ethtool -K veth1 rx off tx off'):
  Host Interface Offload:
    creation time:
     rx checksum
     tx checksum
     tcp segmentation offload
     generic segemanttaion offload
    now:
     generic segemanttaion offload

Signed-off-by: Mohsin Kazmi <[email protected]>
Change-Id: Ia38d35e7a70206781afad42f0333e47bac8fedc9