s390/atomic: refactor atomic primitives

Rework atomic.h to make the low level functions avaible for use
in other headers without using atomic_t, e.g. in bitops.h.

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/pci/pci_debug.c

@@ -69,7 +69,7 @@ static void pci_sw_counter_show(struct seq_file *m)
 	int i;
 
 	for (i = 0; i < ARRAY_SIZE(pci_sw_names); i++, counter++)
-		seq_printf(m, "%26s:\t%llu\n", pci_sw_names[i],
+		seq_printf(m, "%26s:\t%lu\n", pci_sw_names[i],
 			   atomic64_read(counter));
 }