x86: bugfix wbinvd() model check instead of family check

wbinvd is supported on all CPUs 486 or later. But,
pageattr.c is checking x86_model >= 4 before wbinvd(), which looks like
an oversight bug. It was first introduced at one place by changeset
d7c8f21a and got copied over to second
place in the same file later.

[ Impact: fix missing cache flush on early-model CPUs, potential data corruption ]
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/x86/mm/pageattr.c

@@ -153,7 +153,7 @@ static void __cpa_flush_all(void *arg)
 	 */
 	__flush_tlb_all();
 
-	if (cache && boot_cpu_data.x86_model >= 4)
+	if (cache && boot_cpu_data.x86 >= 4)
 		wbinvd();
 }
 
@@ -218,7 +218,7 @@ static void cpa_flush_array(unsigned long *start, int numpages, int cache,
 
 	/* 4M threshold */
 	if (numpages >= 1024) {
-		if (boot_cpu_data.x86_model >= 4)
+		if (boot_cpu_data.x86 >= 4)
 			wbinvd();
 		return;
 	}