s390/cio: export hsch to modules

The vfio-ccw code will need this, and it matches treatment of ssch
and csch.

Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
diff --git a/drivers/s390/cio/ioasm.c b/drivers/s390/cio/ioasm.c
index 14d3283..08eb102 100644
--- a/drivers/s390/cio/ioasm.c
+++ b/drivers/s390/cio/ioasm.c
@@ -233,6 +233,7 @@
 
 	return ccode;
 }
+EXPORT_SYMBOL(hsch);
 
 static inline int __xsch(struct subchannel_id schid)
 {