[S390] sclp: introduce some new interfaces.

Introduce some new interfaces so that random subsystems don't have to
mess around with sclp internal structures.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/char/sclp.h b/drivers/s390/char/sclp.h
index dbb99d1..cb5888f 100644
--- a/drivers/s390/char/sclp.h
+++ b/drivers/s390/char/sclp.h
@@ -72,6 +72,13 @@
 
 typedef u32 sccb_mask_t;	/* ATTENTION: assumes 32bit mask !!! */
 
+struct sccb_header {
+	u16	length;
+	u8	function_code;
+	u8	control_mask[3];
+	u16	response_code;
+} __attribute__((packed));
+
 struct gds_subvector {
 	u8	length;
 	u8	key;