drivers/mhu: derive doorbell base address

In order to allow the MHUv2 driver to be usable with multiple MHUv2
controllers, use the base address of the controller from the platform
information instead of the MHUV2_BASE_ADDR macro.

Change-Id: I4dbab87b929fb0568935e6c8b339ce67937f8cd1
Signed-off-by: Aditya Angadi <aditya.angadi@arm.com>
9 files changed