ANDROID: KVM: arm64: s2mpu: Replace SMC handler with PM callbacks

The host is now expected to notify EL2 about PM state changes of
individual IOMMU devices. Remove the old code that intercepted SMCs
and instead rely on callbacks from the core IOMMU code.

Bug: 190463801
Signed-off-by: David Brazdil <dbrazdil@google.com>
Change-Id: I2dd49836c01e405562ba62c00efc711f084d5963