mei: gsc: setup char driver alive in spite of firmware handshake failure

Setup char device in spite of firmware handshake failure.
In order to provide host access to the firmware status registers and other
information required for the manufacturing process.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220419193314.526966-4-daniele.ceraolospurio@intel.com