iommu/arm-smmu-v3: Stop pre-zeroing batch commands in arm_smmu_atc_inv_master()

Pre-zeroing the batched commands structure is inefficient, as individual
commands are zeroed later in arm_smmu_cmdq_build_cmd(). Therefore, only
the member 'num' needs to be initialized to 0.
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Reviewed-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/20210817113411.1962-1-thunder.leizhen@huawei.comSigned-off-by: Will Deacon <will@kernel.org>

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c

@@ -1764,10 +1764,11 @@ static int arm_smmu_atc_inv_master(struct arm_smmu_master *master)
 {
 	int i;
 	struct arm_smmu_cmdq_ent cmd;
-	struct arm_smmu_cmdq_batch cmds = {};
+	struct arm_smmu_cmdq_batch cmds;
 
 	arm_smmu_atc_inv_to_cmd(0, 0, 0, &cmd);
 
+	cmds.num = 0;
 	for (i = 0; i < master->num_streams; i++) {
 		cmd.atc.sid = master->streams[i].id;
 		arm_smmu_cmdq_batch_add(master->smmu, &cmds, &cmd);