ANDROID: KVM: arm64: Remove 'struct kvm_vcpu' from the KMI

With the addition of 'struct pkvm_module_ops' to the Android-14 KMI, we
inadvertently exposing a number of internal KVM data structures via the
unused '__hyp_running_vcpu' member of 'struct kvm_cpu_context'.

Fix up the KMI by making this field a 'void *' for everybody other than
genksyms.

Cc: Matthias Männich <maennich@google.com>
Cc: Quentin Perret <qperret@google.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Bug: 288146090
Signed-off-by: Will Deacon <willdeacon@google.com>
Change-Id: I54b7fe055830e22e6118779617de2d9259501833