ath9k: Add definitions and structures to support WoW

*add structures, macros and variables for WoW, so that the driver
can make use of it.
*maintain a list for user enabled patterns and masks
*track pattern slots for the hardware limitation on the
maximum number of patterns that can be stored.
*track interrupts enabled before WoW suspend, so
that can be reconfigured after resume
*have macros to parse user defined wow configurations to
hardware code

Cc: Senthil Balasubramanian <senthilb@qca.qualcomm.com>
Cc: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
Cc: vadivel@qca.qualcomm.com
Signed-off-by: Luis R. Rodriguez <mcgrof@qca.qualcomm.com>
Signed-off-by: Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>