MFV r272496:

Add tunable for number of metaslabs per vdev
(vfs.zfs.vdev.metaslabs_per_vdev).  The default remains
at 200.

Illumos issue:
    5161 add tunable for number of metaslabs per vdev

MFC after:	2 weeks


git-svn-id: svn+ssh://svn.freebsd.org/base/head@272507 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Add in decode for the AR9300 RX descriptor.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@272508 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f