'RELENG_5_3_0_RELEASE'.

This commit was manufactured to restore the state of the 5.3-RELEASE image.

Obtained from:	madwifi

o move tx taps from ath_start to ath_tx_start so lots more
  state is available to tap
o add tx flags
o add tx rate
o add tx power (constant for the moment)
o add tx antenna state

o fix race condition when processing rx descriptors: because we use
  a self-linked descriptor at the end of the rx descriptor list to
  avoid rx overruns (which can easily happen for 5212 parts that enable
  PHY errors) we must carefully check that a descriptor is "done" by
  looking ahead to the next descriptor before believing the done bit
  in the current descriptor (this is all handled in the HAL since the
  rx descriptor format is chip-specific so we need to pass in two
  additional parameters--the physical address of the current descriptor
  and the virtual address of the next descriptor in the list)
o check copyout return status for SIOCGATHSTATS ioctl

Approved by:	re (scottl)

we no longer need the debugging code to dump packets.

  quietly discard them; this just permits them to be collected with bpf)
o add a counter for the number of rate control frames discarded when not in
  monitor mode
o move the rx "too short" statistic in the stat structure so non-error rx stats
  are together (NB: ABI change to apps that collect stats via driver ioctl)

Supported by:	Atheros Comunications