mei: me: enable asynchronous probing

On some platforms, currently Broxton, Apollo Lake and Kaby Lake,
ME FW may be busy with internal bookkeeping and answering late
to the start message.
As a mitigation, the driver requests for a synchronous probing
to prevent stalling of the overall boot process. For example,
on a Apollo Lake platform the overall boot time has reduced from
~0.9 to ~0.6 seconds on average.

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