arm-smmu-v3 sharing SID

[Peng Fan]

Hi all,

Current arm-smmu-v3 driver does not support sharing SID,
If there are two devices sharing one SID, the smmu-v3 driver
will report "stream x already in tree".

We have an SOC that using smmu-v3, only supports limited
SIDs. From my understanding, the smmu-v3 hardware
supports SID sharing, but linux driver not support that.

I would like know is it ok to add support for sharing SID?
Something like to use common rb_add/find, not
smmu-v3 driver local rb tree add/find.

Thanks,
Peng.