powerpc/mm/radix: Make sure swapper pgdir is properly aligned

With 4K page size radix config our level 1 page table size is 64K and it
should be naturally aligned.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/head_64.S

@@ -973,13 +973,16 @@ start_here_common:
  * This stuff goes at the beginning of the bss, which is page-aligned.
  */
 	.section ".bss"
+/*
+ * pgd dir should be aligned to PGD_TABLE_SIZE which is 64K.
+ * We will need to find a better way to fix this
+ */
+	.align	16
 
-	.align	PAGE_SHIFT
+	.globl	swapper_pg_dir
+swapper_pg_dir:
+	.space	PGD_TABLE_SIZE
 
 	.globl	empty_zero_page
 empty_zero_page:
 	.space	PAGE_SIZE
-
-	.globl	swapper_pg_dir
-swapper_pg_dir:
-	.space	PGD_TABLE_SIZE