kernel - Adjust BUS_DMASYNC_* API

* Change the BUS_DMASYNC_* enumeration to a bitmask to allow multiple
  flags to be specified in one call.

* Now more compatible with FreeBSD and one less thing to worry about when
  porting a driver.

* While we are at it, allow add_bounce_page() to modify the size.  This has
  no effect on the current codebase since bounce pages are page-aligned (so the
  page-residual will never be less than the passed address), but is more
  correct.

* Fixes bounce-buffer issue with if_ath.
ath - Change the way the edma rxfifo is reset

* Do not unconditionally try to reload the whole FIFO.  Instead set a flag
  when the HAL is reset.

* Force the hal to cold-reset every time for now to match the flag.

* Currently a hack until a Adrian comes up with the correct fix.

* TODO - Currently does not re-enable the RXEOL interrupt correctly.
ath - Change the way the edma rxfifo is reset (2)

* Correct a debugging change that wasn't supposed to go in.
unifdef(1): Update to upstream version 2.10.15.a52596a

Taken-from: http://dotat.at/prog/unifdef/