ath5k: move ath5k_hw_register_timeout() into reset.c

ath5k_hw_register_timeout() was duplicated between phy.c and reset.c.
Since it is too big and too much used to be an inline function, move it
away from the ath5k.h header into reset.c.  Remove _ATH5K_RESET and
_ATH5K_PHY defines.

Signed-off-by: Pavel Roskin <proski@gnu.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>