refactor(tc): append binding for SMMU-700

The usage for SMMU-700 is not consistent across TC platforms:

  SMMU-700 on TC2:

          | FVP   | FPGA
  --------+-------+------
  Display | Used  | Used
  GPU     | Used  | Used

  SMMU-700 on TC3:

          | FVP   | FPGA
  --------+-------+------
  Display | No    | No
  GPU     | Used  | No

This commit changes to use append mode for SMMU-700 to bind it on TC2
and TC3 separately. As a result, the TC_IOMMU_EN configuration is not
used, remove it.

Change-Id: Ic4152eb4c8ef97bf27b8a97c3c6cb86e32a2e8eb
Signed-off-by: Leo Yan <leo.yan@arm.com>
4 files changed