drm/xe: Add XE_ENGINE_CLASS_OTHER to str conversion

XE_ENGINE_CLASS_OTHER was missing from the str conversion. Add it and
remove the default handling so it's protected by -Wswitch.
Currently the only user is xe_hw_engine_class_sysfs_init(), which
already skips XE_ENGINE_CLASS_OTHER, so there's no change in behavior.
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240517204310.88854-3-lucas.demarchi@intel.comSigned-off-by: Lucas De Marchi <lucas.demarchi@intel.com>

drivers/gpu/drm/xe/xe_hw_engine.c

@@ -1111,9 +1111,13 @@ const char *xe_hw_engine_class_to_str(enum xe_engine_class class)
 		return "vecs";
 	case XE_ENGINE_CLASS_COPY:
 		return "bcs";
+	case XE_ENGINE_CLASS_OTHER:
+		return "other";
 	case XE_ENGINE_CLASS_COMPUTE:
 		return "ccs";
-	default:
-		return NULL;
+	case XE_ENGINE_CLASS_MAX:
+		break;
 	}
+
+	return NULL;
 }