[S390] cio: Add chsc subchannel driver.

This patch adds a driver for subchannels of type chsc.

A device /dev/chsc is created which may be used to issue ioctls to:
- obtain information about the machine's I/O configuration
- dynamically change the machine's I/O configuration via
  asynchronous chsc commands

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
diff --git a/include/asm-s390/chpid.h b/include/asm-s390/chpid.h
index b203336..606844d 100644
--- a/include/asm-s390/chpid.h
+++ b/include/asm-s390/chpid.h
@@ -10,7 +10,6 @@
 
 #include <linux/string.h>
 #include <asm/types.h>
-#include <asm/cio.h>
 
 #define __MAX_CHPID 255
 
@@ -41,6 +40,9 @@
 	}
 }
 
+#ifdef __KERNEL__
+#include <asm/cio.h>
+
 static inline int chp_id_is_valid(struct chp_id *chpid)
 {
 	return (chpid->cssid <= __MAX_CSSID);
@@ -49,5 +51,6 @@
 
 #define chp_id_for_each(c) \
 	for (chp_id_init(c); chp_id_is_valid(c); chp_id_next(c))
+#endif /* __KERNEL */
 
 #endif /* _ASM_S390_CHPID_H */