x86/paravirt: Use pte_val instead of pte_flags on CPA pageattr_test

x86/paravirt: Use pte_val instead of pte_flags on CPA pageattr_test

For details refer to patch "x86/paravirt: Use pte_attrs instead of
pte_flags on CPA/set_p.._wb/wc operations." which explains that
some pages have the _PAGE_PWT bit set in the _PAGE_PSE field
when running under Xen.

When pageattr_test is running it uses pte_flags to check whether
it succedded in setting _PAGE_UNUSED1 bit, but also whether the
page had _PAGE_PSE. This can happen when one of the randomly selected
pages to be tested is a page that has been set to be _PAGE_WC
as under Xen, that field is under _PAGE_PSE. Since the 'pte_huge'
call is using the pte_flags(x) macro, which extracts the "raw" contents
of the PTE, the translation of _PAGE_PSE -> _PAGE_PWT does not happen
and we incorrectly identify the PTE as bad.

Using the 'pte_val' instead of 'pte_flags' fixes the problem and
this patch does that.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: stable@kernel.org