No any logical changes, this patch is preparing for multiple active
VMCS12 support.
- currently it's easy to get the vmcs12 pointer from the vcpu pointer.
In multiple active vmcs12 case, we need to explicitly add "struct
acrn_vmcs12 *vmcs12" to certain APIs' input argument list, in order to
get the desired vmcs12 pointer.
- merge flush_current_vmcs12() into clear_vmcs02() for multiple reasons:
a) it's called only once; b) we don't wrap the opposite operation
(loading vmcs12) in an API; c) this API has simple and clear logic.
Tracked-On: #6289
Signed-off-by: Zide Chen <zide.chen@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>