KVM: x86/mmu: Consolidate "is MMIO SPTE" code

mainline inclusion
from mainline-v5.4-rc1
commit 26c44a63
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4MKP4


CVE: NA

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

Replace the open-coded "is MMIO SPTE" checks in the MMU warnings
related to software-based access/dirty tracking to make the code
slightly more self-documenting.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Jackie Liu <liuyun01@kylinos.cn> #openEuler_contributor
Signed-off-by: Laibin Qiu <qiulaibin@huawei.com>
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>