Populate the device info string with _PXM (proximity domain) information.

This is primarily useful for debugging right now - it'll show up in
devinfo.

Reviewed by:	jhb
MSR_KGSBASE is no longer saved and restored from the guest MSR save area. This
behavior was changed in r271888 so update the comment block to reflect this.

MSR_KGSBASE is accessible from the guest without triggering a VM-exit. The
permission bitmap for MSR_KGSBASE is modified by vmx_msr_guest_init() so get
rid of redundant code in vmx_vminit().
Add some more KTR events to help debugging.
Sort the optional rc.d scripts by their knobs

MFC after: 1 week
Sponsored by: EMC / Isilon Storage Division
Don't install /etc/rc.d/rwho unless MK_RCMDS == yes

MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division
Don't install /etc/rc.d/ftp-proxy unless MK_PF == yes

MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division
Make gcc happy by initialising the variable only set in a couple of
case statements without a default.

MFC after:	2 days
X-MFC with:	r271871
Properly hide calls to ARP under #ifdef INET to allow IPv6-only
kernels to compile.

MFC atfer:	3 days
Fix typo in comment.
Disable AHB clock gate for ehci0.

Approved by:	stas (mentor)