[S390] sparse: fix sparse static warnings

Make functions and data static to avoid sparse warnings.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/boot/compressed/misc.c b/arch/s390/boot/compressed/misc.c
index 028f23e..465eca7 100644
--- a/arch/s390/boot/compressed/misc.c
+++ b/arch/s390/boot/compressed/misc.c
@@ -61,7 +61,7 @@
 
 extern _sclp_print_early(const char *);
 
-int puts(const char *s)
+static int puts(const char *s)
 {
 	_sclp_print_early(s);
 	return 0;