arm64/mm: Ensure PGD_SIZE is aligned to 64 bytes when PA_BITS = 52

Although the comment clearly states about PGD table's alignment requirement
(when PA_BITS = 52) but the subsequent BUILD_BUG_ON() tests size comparison
to 64 bytes instead. So change it as an actual alignment test.

Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Author: Anshuman Khandual

arch/arm64/mm/pgd.c

@@ -56,7 +56,7 @@ void __init pgtable_cache_init(void)
 	 * With 52-bit physical addresses, the architecture requires the
 	 * top-level table to be aligned to at least 64 bytes.
 	 */
-	BUILD_BUG_ON(PGD_SIZE < 64);
+	BUILD_BUG_ON(!IS_ALIGNED(PGD_SIZE, 64));
 #endif
 
 	/*