iommu: arm-smmu: Reinitialize domain properly on error paths

Ensure the error paths from arm_smmu_init_domain() context clean
up properly. This relies on testing for some "magic values" which
indicate whether irqs/context banks/ etc have been initialized.

Ensure the "magic values" are reset so a future call to
arm_smmu_init_domain() has the same behavior.

Change-Id: I6d86fe548631a0dd82f5535f79b66c1ff9d729c3
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>