mei: txe: add hw-txe.h header file

This header file add mei_txe_hw structure
that hold txe hw specific state and other sw constructs.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>