KVM: arm64: Prevent unsupported memslot operations on protected VMs

KVM: arm64: Prevent unsupported memslot operations on protected VMs

Protected VMs do not support deleting or moving memslots after first
run nor do they support read-only or dirty logging.

Return -EPERM to userspace if such an operation is attempted.

Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Link: https://patch.msgid.link/20260330144841.26181-10-will@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>