for AR9002 family of chipsets and for WoW sleep, we reprogram
the SerDes so that the PLL and CHK REQ are both enabled. this
uses more power but in certain cases this is required as otherwise
WoW sleep is unstable and chip may disappear.

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>