s390: make various functions static, add declarations to header files

Make various functions static, add declarations to header files to
fix a couple of sparse findings.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 1224db4..4645faf 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -958,7 +958,7 @@
 	tlb_remove_table(tlb, table);
 }
 
-void __tlb_remove_table(void *_table)
+static void __tlb_remove_table(void *_table)
 {
 	const unsigned long mask = (FRAG_MASK << 4) | FRAG_MASK;
 	void *table = (void *)((unsigned long) _table & ~mask);