[S390] cio: CHSC SIOSL Support

A Linux interface for the CHSC command
store-I/O-operation-status-and-initiate-logging (SIOSL).
Model-dependent logging within the channel subsystem can be invoked
via a helper function or a writable subchannel device attribute.

Signed-off-by: Michael Ernst <mernst@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/cio/chsc.h

@@ -80,4 +80,6 @@ int chsc_get_channel_measurement_chars(struct channel_path *chp);
 
 int chsc_error_from_response(int response);
 
+int chsc_siosl(struct subchannel_id schid);
+
 #endif