e1000e: Separate ADP board type from TGP

We have the same LAN controller on different PCH's. Separate ADP board
type from a TGP which will allow for specific fixes to be applied for
ADP platforms.

Suggested-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Suggested-by: Dima Ruinskiy <dima.ruinskiy@intel.com>
Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Nechama Kraus <nechamax.kraus@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>