x86: Fix up silly i1586 boot message.

Trying to boot a 64-bit kernel on a 32bit Pentium 4 gets
you an amusing message along the lines of.
"you need an x86-64, but you only have an i1586"
due to the P4 being family F.  Munge it to be 686.
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/x86/boot/cpu.c

@@ -28,6 +28,8 @@ static char *cpu_name(int level)
 	if (level == 64) {
 		return "x86-64";
 	} else {
+		if (level == 15)
+			level = 6;
 		sprintf(buf, "i%d86", level);
 		return buf;
 	}