[S390] Get rid of a lot of sparse warnings.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/include/asm-s390/pgtable.h b/include/asm-s390/pgtable.h
index ae61aca..304ee77 100644
--- a/include/asm-s390/pgtable.h
+++ b/include/asm-s390/pgtable.h
@@ -40,6 +40,7 @@
 
 extern pgd_t swapper_pg_dir[] __attribute__ ((aligned (4096)));
 extern void paging_init(void);
+extern void vmem_map_init(void);
 
 /*
  * The S390 doesn't have any external MMU info: the kernel page