- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Further arswitch work:

* Add in the AR724x support. It probes the same as an AR8216/AR8316, so
just add in a hint to force the probe success rather than auto-detecting
it.

* Add in the missing entries from conf/files, lacking in the previous
commit.

The register values and CPU port / mirror port initialisation value was
obtained from Linux OpenWRT ag71xx_ar7240.c.

The DELAY(1000) to let things settle is my local workaround. For some
reason, PHY4 doesn't seem to probe very reliably without it. It's quite
possible that we're missing some MDIO bus initialisation code in if_arge
for the AR724x case. As I dislike DELAY() workarounds in general, it's
definitely worth trying to figure out why this is the case.

Tested on: AP93 (AR7240) reference design

Obtained from: Linux OpenWRT