Rework mei power gating state machine to support entry and exit to and
from D0i3 power state.
The choice between legacy and D0i3 routines is conditioned on
d0i3_supported flag.

The patch introduces warning:
drivers/misc/mei/hw-me.c:901:12: warning: ‘mei_me_d0i3_enter’ defined but not used [-Wunused-function]
it will go away in consequent patch
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>