ar5523: Add new driver

This driver is for the AR5523 chipset from Atheros. It was created
in 2007 by Christoph Hellwig but it was never finished. I found it a
couple of months ago and after some polishing it's working pretty
fine.

The driver was written with the FreeBSD driver (uath) as reference,
which was written with the reverse-engineered windows driver as
reference, hence the feature set is very limited. Station mode
only, no HW crypto offload.

Signed-off-by: Pontus Fuchs <pontus.fuchs@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/Makefile

@@ -2,6 +2,7 @@ obj-$(CONFIG_ATH5K)		+= ath5k/
 obj-$(CONFIG_ATH9K_HW)		+= ath9k/
 obj-$(CONFIG_CARL9170)		+= carl9170/
 obj-$(CONFIG_ATH6KL)		+= ath6kl/
+obj-$(CONFIG_AR5523)		+= ar5523/
 
 obj-$(CONFIG_ATH_COMMON)	+= ath.o