KVM: x86: Don't clear PIT's IRQ line status when destroying PIT

KVM: x86: Don't clear PIT's IRQ line status when destroying PIT

Don't bother clearing the PIT's IRQ line status when destroying the PIT,
as userspace can't possibly rely on KVM to lower the IRQ line in any sane
use case, and it's not at all obvious that clearing the PIT's IRQ line is
correct/desirable in kvm_create_pit()'s error path.

When called from kvm_arch_pre_destroy_vm(), the entire VM is being torn
down and thus {kvm_pic,kvm_ioapic}.irq_states are unreachable.

As for the error path in kvm_create_pit(), the only way the PIT's bit in
irq_states can be set is if userspace raises the associated IRQ before
KVM_CREATE_PIT{2} completes.  Forcefully clearing the bit would clobber
userspace's input, nonsensical though that input may be.  Not to mention
that no known VMM will continue on if PIT creation fails.

Acked-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20250611213557.294358-12-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>