ANDROID: KVM: arm64: Free shadow data vCPUs memcache

In protected mode, shadow VM structures are created at EL2. They include
shadow vCPUs and their memcache where some pages donated by the host might
be temporarily stored. They need to be freed on VM teardown to not get
lost. Pages found there have not been used for anything by the hypervisor.
Clearing is therefore not necessary.

Bug: 237506543
Change-Id: Ic37d794ac33e9f844fa6ae1b4943febcdad5b033
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>