iommu/arm-smmu-v3: Extract reusable function __arm_smmu_cmdq_skip_err()

iommu/arm-smmu-v3: Extract reusable function __arm_smmu_cmdq_skip_err()

When SMMU_GERROR.CMDQP_ERR is different to SMMU_GERRORN.CMDQP_ERR, it
indicates that one or more errors have been encountered on a command queue
control page interface. We need to traverse all ECMDQs in that control
page to find all errors. For each ECMDQ error handling, it is much the
same as the CMDQ error handling. This common processing part is extracted
as a new function __arm_smmu_cmdq_skip_err().

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20210811114852.2429-5-thunder.leizhen@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>