For 6x00 2x2 NIC, two types of Power Amplifier are available.
In order for uCode to apply correct tx power,
driver needs to program the CSR_GP_DRIVER_REG register and
let uCode know the type of PA.
If driver do not program CSR_GP_DRIVER_REG register (default to 0),
then it is uCode's decision for tx power

2x2 Hybrid card: use both internal and external PA
2x2 IPA(Internal Power Amplifier) card: internal PA only
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>