KVM: SVM: Initialize per-CPU svm_data at the end of hardware setup

KVM: SVM: Initialize per-CPU svm_data at the end of hardware setup

Setup the per-CPU SVM data structures at the very end of hardware setup so
that svm_hardware_unsetup() can be used in svm_hardware_setup() to unwind
AVIC setup (for the GALog notifier).  Alternatively, the error path could
do an explicit, manual unwind, e.g. by adding a helper to free the per-CPU
structures.  But the per-CPU allocations have no interactions or
dependencies, i.e. can comfortably live at the end, and so converting to
a manual unwind would introduce churn and code without providing any
immediate advantage.

Link: https://patch.msgid.link/20251016190643.80529-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>