iommu/iova: Support disabling domain iova alignment

Currently the IOVA framework automatically applies IOVA alignment to
provided IOVAs based on the requested IOVA size and the alignment configs
which are enabled.

Some clients who don't require any IOVA alignment would benefit from the
reduced fragmentation that would result from disabling IOVA alignment.

Add support to allow clients to disable IOVA alignment on an IOMMU domain.

Change-Id: Ifa6a75576e7a084c443abf38726d790b883f00b3
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
[lmark@codeaurora.org: cleanup change]
Signed-off-by: Liam Mark <lmark@codeaurora.org>