ath5k: debug level improvements

ath5k: debug level improvements

* use only one debug level for beacon debugging: unify ATH5K_DEBUG_BEACON and
ATH5K_DEBUG_BEACON_PROC.

* remove debug level ATH5K_DEBUG_FATAL. doesn't make sense as a debug level -
if it's fatal it should be logged as an error.

* fancier printing of debug levels. cat /debugfs/ath5k/phy0/debug.

* allow debug levels to be changed by echoing their name into
/debugfs/ath5k/phy0/debug. this will toggle the state, when it was off it will
be turned on and vice versa.

* use copy_from_user() when reading from the debug files. use unsigned int for
better optimization. reduce buffer sizes on stack.

drivers/net/wireless/ath5k/base.c:      Changes-licensed-under: 3-Clause-BSD
drivers/net/wireless/ath5k/debug.c:     Changes-licensed-under: GPL
drivers/net/wireless/ath5k/debug.h:     Changes-licensed-under: GPL

Signed-off-by: Bruno Randolf <bruno@thinktube.com>
Acked-by: Luis R. Rodriguez <mcgrof@winlab.rutgers.edu>
Acked-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>