s390/mm: align swapper_pg_dir to 16k

The segment/region table that is part of the kernel image must be
properly aligned to 16k in order to make the crdte inline assembly
work.
Otherwise it will calculate a wrong segment/region table start address
and access incorrect memory locations if the swapper_pg_dir is not
aligned to 16k.

Therefore define BSS_FIRST_SECTIONS in order to put the swapper_pg_dir
at the beginning of the bss section and also align the bss section to
16k just like other architectures did.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 3038edb..37e1aa9 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -32,7 +32,7 @@
 #include <asm/bug.h>
 #include <asm/page.h>
 
-extern pgd_t swapper_pg_dir[] __attribute__ ((aligned (4096)));
+extern pgd_t swapper_pg_dir[];
 extern void paging_init(void);
 extern void vmem_map_init(void);
 pmd_t *vmem_pmd_alloc(void);