kvm: fix previous commit for 32-bit builds

stable inclusion
from stable-v4.19.195
commit 270dadd7ea31c1bc43a0b1de118a30c2238171a8
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9R4K5


CVE: CVE-2021-47277

--------------------------------

commit 4422829e upstream.

array_index_nospec does not work for uint64_t on 32-bit builds.
However, the size of a memory slot must be less than 20 bits wide
on those system, since the memory slot must fit in the user
address space.  So just store it in an unsigned long.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>