lguest: accept guest _PAGE_PWT page table entries

Beginning from commit 4138cc34, ioremap_nocache() sets the _PAGE_PWT
flag.

Lguest doesn't accept a guest pte with a _PWT flag and reports a "bad
page table entry" in that case.

Accept guest _PAGE_PWT page table entries.
Signed-off-by: NAhmed S. Darwish <darwish.07@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

drivers/lguest/page_tables.c

@@ -178,8 +178,8 @@ static void release_pte(pte_t pte)
 
 static void check_gpte(struct lg_cpu *cpu, pte_t gpte)
 {
-	if ((pte_flags(gpte) & (_PAGE_PWT|_PAGE_PSE))
-	    || pte_pfn(gpte) >= cpu->lg->pfn_limit)
+	if ((pte_flags(gpte) & _PAGE_PSE) ||
+	    pte_pfn(gpte) >= cpu->lg->pfn_limit)
 		kill_guest(cpu, "bad page table entry");
 }