drm/i915/guc: Prepare send() function to accept bigger response

This is a preparation step for the upcoming patches.
We already can return some small data decoded from the command
status, but we will need more in the future.

v2: add explicit response buf size
v3: squash with helper patch

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Oscar Mateo <oscar.mateo@intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Michel Thierry <michel.thierry@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180326194829.58836-4-michal.wajdeczko@intel.com

drivers/gpu/drm/i915/intel_guc.c

@@ -310,7 +310,8 @@ void intel_guc_init_params(struct intel_guc *guc)
 	intel_uncore_forcewake_put(dev_priv, FORCEWAKE_BLITTER);
 }
 
-int intel_guc_send_nop(struct intel_guc *guc, const u32 *action, u32 len)
+int intel_guc_send_nop(struct intel_guc *guc, const u32 *action, u32 len,
+		       u32 *response_buf, u32 response_buf_size)
 {
 	WARN(1, "Unexpected send: action=%#x\n", *action);
 	return -ENODEV;
@@ -319,7 +320,8 @@ int intel_guc_send_nop(struct intel_guc *guc, const u32 *action, u32 len)
 /*
  * This function implements the MMIO based host to GuC interface.
  */
-int intel_guc_send_mmio(struct intel_guc *guc, const u32 *action, u32 len)
+int intel_guc_send_mmio(struct intel_guc *guc, const u32 *action, u32 len,
+			u32 *response_buf, u32 response_buf_size)
 {
 	struct drm_i915_private *dev_priv = guc_to_i915(guc);
 	u32 status;