x86/apic: Support LAPIC timer for Secure AVIC

x86/apic: Support LAPIC timer for Secure AVIC

Secure AVIC requires the LAPIC timer to be emulated by the hypervisor.  KVM
already supports emulating the LAPIC timer using hrtimers. In order to emulate
it, APIC_LVTT, APIC_TMICT and APIC_TDCR register values need to be propagated
to the hypervisor for arming the timer.  APIC_TMCCT register value has to be
read from the hypervisor, which is required for calibrating the APIC timer.
So, read/write all APIC timer registers from/to the hypervisor.

Co-developed-by: Kishon Vijay Abraham I <kvijayab@amd.com>
Signed-off-by: Kishon Vijay Abraham I <kvijayab@amd.com>
Signed-off-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tianyu Lan <tiala@microsoft.com>
Link: https://lore.kernel.org/20250828110926.208866-1-Neeraj.Upadhyay@amd.com