The iavf(4) driver now uses a different source base from ixl(4), since
it will be the standard VF driver for new Intel Ethernet products going forward,
including ice(4).
Since it now uses different source code, this commit adds a new sys/dev/iavf
entry, but it re-uses the existing module name so no configuration changes are
necessary.
Signed-off-by: Eric Joyner <erj@FreeBSD.org>