KVM: arm64: Stub CONFIG_DEBUG_LIST at Hyp

In order to use the kernel list library at EL2, introduce stubs for the
CONFIG_DEBUG_LIST out-of-lines calls.

Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210319100146.1149909-12-qperret@google.com