feat(gic600ae_fmu): disable SMID for unavailable blocks

This patch updates the gic600_fmu_init function to disable all safety
mechanisms for a block ID that is not present on the platform. All
safety mechanisms for GIC-600AE are enabled by default and should be
disabled for blocks that are not present on the platform to avoid
false positive RAS errors.

Change-Id: I52dc3bee9a8b49fd2e51d7ed851fdc803a48e6e3
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>