KVM: nVMX: Fix injection of PENDING_INTERRUPT and NMI_WINDOW exits to L1

Check if the interrupt or NMI window exit is for L1 by testing if it has
the corresponding controls enabled. This is required when we allow
direct injection from L0 to L2

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>