ANDROID: GKI: x86: Enable pKVM-IA

Although pKVM-IA is enabled in kconfig, by default kernel is not
running in pkvm mode until extra command line flag "kvm-intel.pkvm=1"
is provided.

Bug: 349990461
Bug: 379814782
Test: Android can run protected VMs

Change-Id: I1a9a1e66f96c360a11bcee510f622ad8c79b2541
Signed-off-by: Tomasz Nowicki <tnowicki@google.com>