Remove an un-needed comment.
wordexp(): Remove wrong IFS usage.

Words in shell script are separated by spaces or tabs independent of the
value of IFS. The value of IFS is only relevant for the result of
substitutions. Therefore, there should be a space between 'wordexp' and the
words to be expanded, not an IFS character.

Paranoia might dictate that the shell ignore IFS from the environment (even
though our sh currently uses it), so do not depend on it in the new test
case.
Ensure that we only call the busdma unmap/flush routines once, when
the buffer is being freed.

* When buffers are cloned, the original mapping isn't copied but it
  wasn't freeing the mapping until later.  To be safe, free the
  mapping when the buffer is cloned.

* ath_freebuf() now no longer calls the busdma sync/unmap routines.

* ath_tx_freebuf() now calls sync/unmap.

* Call sync first, before calling unmap.

Tested:

* AR5416, STA mode
Follow up to r247960 and rr247960 by also amending ctfmerge.  For the
only other case where STT_FILE symbols are used, in symit_next() in
cddl/contrib/opensolaris/tools/ctf/cvt/input.c, save the basename of the
symbol, instead of the full pathname.

Reported by:	avg
Tested by:	avg, jimharris
MFC after:	1 week