iommu: Add group variant for SVA bind/unbind

maillist inclusion
category: feature
bugzilla: 51855
CVE: NA

Reference: https://jpbrucker.net/git/linux/commit/?h=sva/2021-03-01&id=7984f27d63b2f56dcdc106be9484061b3a13df0b



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VFIO works directly with IOMMU groups rather than devices. Even if groups
ar still required to only contain one device in order to use SVA, add a
set of helpers for VFIO.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Lijun Fang <fanglijun3@huawei.com>
Reviewed-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>