fix #26319040

commit b9c6ff94e43a0ee053e0c1d983fba1ac4953b762 upstream.

Re-factore the logic for activate/deactivate guest virtual APIC mode
(GAM)
into helper functions, and export them for other drivers (e.g. SVM).
to support run-time activate/deactivate of SVM AVIC.

Cc: Joerg Roedel <joro@8bytes.org>
Signed-off-by: NSuravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: Ntianyi <fujunkang@linux.alibaba.com>
Reviewed-by: Nzhangliguang <zhangliguang@linux.alibaba.com>
Acked-by: Nzhangliguang <zhangliguang@linux.alibaba.com>