ath9k_hw: Add WoW hardware capability flags

have seperate wow capability flags for
*basic wow support
*device capable of matching exact user defined pattern
or de-authentication/disassoc pattern
*device such AR9280 requires first four bytes for
all sort of patterns

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>