x86: CPA: fix gbpages support in try_preserve_large_page

[ mingo@elte.hu: while gbpages cannot be enabled on mainline currently,
  keep the code uptodate and this fix is easy enough. ]

Use correct page sizes and masks for GB pages in try_preserve_large_page()

This prevents a boot hang on a GB capable system with CONFIG_DIRECT_GBPAGES
enabled.
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

arch/x86/mm/pageattr.c

@@ -275,8 +275,8 @@ try_preserve_large_page(pte_t *kpte, unsigned long address,
 		break;
 #ifdef CONFIG_X86_64
 	case PG_LEVEL_1G:
-		psize = PMD_PAGE_SIZE;
-		pmask = PMD_PAGE_MASK;
+		psize = PUD_PAGE_SIZE;
+		pmask = PUD_PAGE_MASK;
 		break;
 #endif
 	default: