Quote Avi's comment:
| KVM_MEMSLOT_INVALID is actually an internal symbol, not used by
| userspace.  Please move it to kvm_host.h.

Also, we divide the memlsot->flags into two parts, the lower 16 bits
are visible for userspace, the higher 16 bits are internally used in
kvm
Signed-off-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>