ethernet: Retire M_HASFCS
The mbuf flag M_HASFCS was introduced for drivers to indicate the net
stack that packets include FCS (Frame Check Sequence). In principle, to
be efficient, FCS should always be processed by hardware, firmware, or
at last sort the driver. Well, Ethernet specifies that damaged frames
should be discarded, thus only good ones will be passed up to the net
stack, then it makes no senses for the net stack to see FCS just to trim
it.
The last consumer of the flag M_HASFCS has been removed since change [1].
It is time to retire it.
- 105a4f7b3cb6 ng_atmllc: remove
Reviewed by: kp
MFC after: never
Differential Revision: https://reviews.freebsd.org/D42391