drm/i915: Add GuC-related module parameters

Two new module parameters: "enable_guc_submission" which will turn
on submission of batchbuffers via the GuC (when implemented), and
"guc_log_level" which controls the level of debugging logged by the
GuC and captured by the host.
Signed-off-by: Alex Dai <yu.dai@intel.com>

v4:
    Mark "enable_guc_submission" unsafe [Daniel Vetter]
Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
Reviewed-by: Tom O'Rourke <Tom.O'Rourke@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

@@ -2610,6 +2610,8 @@ struct i915_params {
 	bool reset;
 	bool disable_display;
 	bool disable_vtd_wa;
+	bool enable_guc_submission;
+	int guc_log_level;
 	int use_mmio_flip;
 	int mmio_debug;
 	bool verbose_state_checks;

drivers/gpu/drm/i915/i915_params.c

@@ -52,6 +52,8 @@ struct i915_params i915 __read_mostly = {
 	.mmio_debug = 0,
 	.verbose_state_checks = 1,
 	.edp_vswing = 0,
+	.enable_guc_submission = false,
+	.guc_log_level = -1,
 };
 
 module_param_named(modeset, i915.modeset, int, 0400);
@@ -181,3 +183,10 @@ MODULE_PARM_DESC(edp_vswing,
 		 "Ignore/Override vswing pre-emph table selection from VBT "
 		 "(0=use value from vbt [default], 1=low power swing(200mV),"
 		 "2=default swing(400mV))");
+
+module_param_named_unsafe(enable_guc_submission, i915.enable_guc_submission, bool, 0400);
+MODULE_PARM_DESC(enable_guc_submission, "Enable GuC submission (default:false)");
+
+module_param_named(guc_log_level, i915.guc_log_level, int, 0400);
+MODULE_PARM_DESC(guc_log_level,
+	"GuC firmware logging level (-1:disabled (default), 0-3:enabled)");