kvm: decode the argument of KVM_SET_USER_MEMORY_REGION ioctl command

kvm: decode the argument of KVM_SET_USER_MEMORY_REGION ioctl command

* configure.ac (AC_CHECK_TYPES): Add struct kvm_userspace_memory_region.
* xlat/kvm_mem_flags.in: New file.
* kvm.c: Include print_fields.h.
[HAVE_STRUCT_KVM_USERSPACE_MEMORY_REGION]: Include xlat/kvm_mem_flags.h,
(kvm_ioctl_set_user_memory_region): New function.
(kvm_ioctl) [HAVE_STRUCT_KVM_USERSPACE_MEMORY_REGION]
<KVM_SET_USER_MEMORY_REGION>: Use it.

Signed-off-by: Masatake YAMATO <yamato@redhat.com>