Fix partition alignment and image rounding when any of -P (block size),
-T (track size) or -H (number of heads) is given:
o   scheme_metadata() always rounded to the block size.  This is not
    always valid (e.g. vtoc8 that must have partitions start at cylinder
    boundaries).
o   The bsd and vtoc8 schemes "resized" the image to make it match the
    geometry, but since the geometry is an approximation and the size
    of the image computed from cylinders * heads * sectors is always
    smaller than the original image size, the partition information ran
    out of bounds.

The fix is to have scheme_metadata() simply pass it's arguments to the
per-scheme metadata callback, so that schemes not only know where the
metadata is to go, but also what the current block address is. It's now
up to the per-scheme callback to reserve room for metadata and to make
sure alignment and rounding is applied.

The BSD scheme now has the most elaborate alignment and rounding. Just
to make the point: partitions are aligned on block boundaries, but the
image is rounded to the next cyclinder boundary.

vtoc8 now properly has all partitions aligned (and rounded) to the
cyclinder boundary.

Obtained from:	Juniper Networks, Inc.
MFC after:	3 days
Style (9) fixes, spaces to tabs.

Fix style issues noticed when I went to MFC r257820

MFC after:	2 days
X-MFC-With:	r257820
Sponsored by:	Multiplay
Explain how to load the malo(4) firmware on boot.

PR:		193653
Submitted by:	Juan Ramón Molina Menor
MFC after:	3 days
Don't double-call the ar9300 stub function method.
Quieten the AR9300 HAL probe a bit.
Quieten the AR9300 HAL attach a little - the setupXTxDesc method
is only called during attach now.

The EDMA TX path never calls this - only the legacy TX path does.
Fix up the EDMA RX setup path to correctly initialise and reset the RX FIFO.

The original code was .. well, slightly more than incorrect.

It showed up as stalled RX queues if the NIC needed to be frequently
reinitialised (eg during scans.)

This is inspired by work done by Matt Dillon over at the DragonflyBSD
project.

So:

* track when EDMA RX has been stopped and when the MAC has been reset;
* re-initialise the ring only after a reset;
* track whether RX has been stopped/started - just for debugging now;
* don't bother with the RX EOL stuff for EDMA - we don't need the
  interrupt at all.  We also don't need to disable/enable the interrupt
  or start DMA - once new frames are pushed into the ring via the
  normal RX path, it'll just restart RX DMA on its own.

Tested:

* AR9380, STA mode
* AR9380, AP mode
* AR9485, STA mode
* AR9462, STA mode
Restructure the MSR handling so it is entirely handled by processor-specific
code. There are only a handful of MSRs common between the two so there isn't
too much duplicate functionality.

The VT-x code has the following types of MSRs:

- MSRs that are unconditionally saved/restored on every guest/host context
  switch (e.g., MSR_GSBASE).

- MSRs that are restored to guest values on entry to vmx_run() and saved
  before returning. This is an optimization for MSRs that are not used in
  host kernel context (e.g., MSR_KGSBASE).

- MSRs that are emulated and every access by the guest causes a trap into
  the hypervisor (e.g., MSR_IA32_MISC_ENABLE).

Reviewed by:	grehan