iommu/io-pgtable-arm: Factor out ARM LPAE register defines

hulk inclusion
category: feature
bugzilla: 14369
CVE: NA
-------------------

For SVA, we'll need to extract CPU page table information and mirror it in
the substream setup. Move relevant defines to a common header.

Fix TCR_SZ_MASK while we're at it.

Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: Fang Lijun <fanglijun3@huawei.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Reviewed-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>