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 <[e-mail]>
Reviewed-by: Halil Pasic <[e-mail]>
Signed-off-by: Cornelia Huck <[e-mail]>

drivers/s390/cio/ioasm.c

···
 
 	return ccode;
 }
+EXPORT_SYMBOL(hsch);
 
 static inline int __xsch(struct subchannel_id schid)
 {