Properly report 12Gbps connection rate.

Reviewed by:	kadesai, slm
MFC after:	1 week


git-svn-id: svn+ssh://svn.freebsd.org/base/head@272756 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Add schedgraph traces for callout handlers.  Specifically, a callwheel logs
a running event each time it executes a callout function.  The event
includes the function pointer, argument, and whether or not it was run from
hardware interrupt context.  The callwheel is marked idle when each handler
completes.  This effectively logs the duration of each callout routine in
the graph.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@272757 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f