It is safer to setup valid send function after successful GuC
hardware initialization. In addition we prepare placeholder
where we can setup any alternate GuC communication mechanism.
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170502103243.54940-1-michal.wajdeczko@intel.com
[ickle: Fixup ENODEV for an impossible error path]
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>