- 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

MFC r256308:

Do not provide a hint of the guest's OS version

The calculation can overflow if __FreeBSD_version is big
enough, and it does not appear to be required.

Approved by: re (gjb)

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

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

Few more minor if_vmx tweaks

- Allow the Rx/Tx queue sizes to be configured by tunables
- Bail out earlier if the Tx queue unlikely has enough free
descriptors to hold the frame
- Cleanup some of the offloading capabilities handling

Couple minor if_vmx tweaks

- Use queue size fields from the Tx/Rx queues in various places
instead of (currently the same values) from the softc.
- Fix potential crash in detach if the attached failed to alloc
queue memory.
- Move the VMXNET3_MAX_RX_SEGS define to a better spot.
- Tweak frame size calculation w.r.t. ETHER_ALIGN. This could be
tweaked some more, or removed since it probably doesn't matter
much for x86 (and the x86 class of machines this driver will
be used on).

Add vmx(4), a VMware VMXNET3 ethernet driver ported from OpenBSD