iommu/io-pgtable: Add support for io-pgtable accounting

The operations for managing io-pgtable memory were recently
updated, and do not account for io-pgtable memory accounting.
Add support to the new operations, so that the amount of io-pgtable
memory in use can be tracked. Also, the amount of overhead that
the io-pgtable accounting feature adds is negligible, so enable
it in the consolidate defconfig, as opposed to the debug defconfig.

Change-Id: I79d9ec2b5196096c4961e4d902c2f0e9a5ccd909
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>