staging: ath6kl: remove-typedef AR6K_ASYNC_REG_IO_BUFFER

remove-typedef -s AR6K_ASYNC_REG_IO_BUFFER \
	"struct ar6k_async_reg_io_buffer" drivers/staging/ath6kl/

Cc: Naveen Singh <naveen.singh@atheros.com>
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>