GUC_CTB_MSG_0_FORMAT
u32 format = FIELD_GET(GUC_CTB_MSG_0_FORMAT, msg->msg[0]);
header = FIELD_PREP(GUC_CTB_MSG_0_FORMAT, GUC_CTB_FORMAT_HXG) |
cmd[0] = FIELD_PREP(GUC_CTB_MSG_0_FORMAT, GUC_CTB_FORMAT_HXG) |