drm/i915: Enable multi-bb execbuf

Enable multi-bb execbuf by enabling the set_parallel extension.
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211014172005.27155-25-matthew.brost@intel.com

drivers/gpu/drm/i915/gem/i915_gem_context.c

@@ -570,9 +570,6 @@ set_proto_ctx_engines_parallel_submit(struct i915_user_extension __user *base,
 	struct intel_engine_cs **siblings = NULL;
 	intel_engine_mask_t prev_mask;
 
-	/* Disabling for now */
-	return -ENODEV;
-
 	/* FIXME: This is NIY for execlists */
 	if (!(intel_uc_uses_guc_submission(&i915->gt.uc)))
 		return -ENODEV;