KVM-async_pf: Delete an unnecessary check before the function call "kmem_cache_destroy"

SF Markus Elfring acpica-devel alsa-devel ath10k ath9k-devel backports batman ceph-devel cluster-devel cocci dm-devel dri-devel ecryptfs intel-gfx kernel-janitors kvm linux-acpi linux-arm-kernel linux-arm-msm linux-audit linux-bcache linux-block linux-bluetooth linux-btrfs linux-crypto linux-devicetree linux-ext4 linux-f2fs-devel linux-fbdev linux-fsdevel linux-gpio linux-hwmon linux-ia64 linux-ide linux-input linux-iommu linux-kbuild linux-media linux-mediatek linux-mm linux-mtd linux-nfs linux-nilfs linux-nvdimm linux-omap linux-parisc linux-pci linux-pm linux-ppp linux-pwm linux-raid linux-rdma linux-rockchip linux-s390 linux-samsung-soc linux-scsi linux-sctp linux-sh linux-spi linux-tegra linux-wireless linux-wpan linux-xfs linuxppc-dev lkml lustre-devel lvs-devel netdev netfilter-devel nouveau nvdimm ocfs2-devel platform-driver-x86 virtualization xen-devel 1 version Nov 15, 2015 Applied

Status from this message: Applied to kvm/queue, thanks.