Remove ifq_drops from struct ifqueue. Now queue drops are accounted in
struct ifnet if_oqdrops.

Some netgraph modules used ifqueue w/o ifnet. Accounting of queue drops
is simply removed from them. There were no API to read this statistic.

Sponsored by:	Netflix
Sponsored by:	Nginx, Inc.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271856 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Mechanically convert to if_inc_counter().


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271857 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Mechanically convert to if_inc_counter().


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271858 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Mechanically convert to if_inc_counter().


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271859 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Mechanically convert to if_inc_counter().


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271860 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Mechanically convert to if_inc_counter().


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271861 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f