ARM: 8494/1: mm: Enable PXN when running non-LPAE kernel on LPAE processor

The VMSA field of MMFR0 (bottom 4 bits) is incremented for each
added feature.  PXN is supported if the value is >= 4 and LPAE
is supported if it is >= 5.

In case a kernel with CONFIG_ARM_LPAE disabled is used on a
processor that supports LPAE, we can still use PXN in short
descriptors.  So check for >= 4 not == 4.

Signed-off-by: Jungseung Lee <js07.lee@samsung.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/mmu.c

@@ -572,7 +572,7 @@ static void __init build_mem_type_table(void)
 	 * in the Short-descriptor translation table format descriptors.
 	 */
 	if (cpu_arch == CPU_ARCH_ARMv7 &&
-		(read_cpuid_ext(CPUID_EXT_MMFR0) & 0xF) == 4) {
+		(read_cpuid_ext(CPUID_EXT_MMFR0) & 0xF) >= 4) {
 		user_pmd_table |= PMD_PXNTABLE;
 	}
 #endif