ANDROID: drivers/arm-smmu-v3-kvm: Fix pgsize alignment for IDMAP

When mapping pages in the identity mapped domain,the driver chooses
the most optimal page size based on the requested size.
However, this must be also be aligned to the address.

Bug: 277989609
Bug: 278749606

Change-Id: Id442198eaf33be6b18f3e5198e2f365e279ff6b5
Signed-off-by: Mostafa Saleh <smostafa@google.com>