KVM: VMX: Move posted interrupt descriptor out of VMX code

[ Upstream commit 699f6751 ]

To prepare native usage of posted interrupts, move the PID declarations out
of VMX code such that they can be shared.

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20240423174114.526704-2-jacob.jun.pan@linux.intel.com


Stable-dep-of: d83c36d8 ("KVM: nVMX: Add a helper to get highest pending from Posted Interrupt vector")
Signed-off-by: Sasha Levin <sashal@kernel.org>