s390/sclp_sdias: Add missing break and "fall through"

If the last block of the HSA is read, EVSTATE_ALL_STORED is returned
by SCLP. Because of a missing break in the switch statement two trace
entries are written in this case: "all stored" and "part stored".

This patch adds the missing break and also adds a "fall through"
comment to improve the readability.
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Reported-by: David A Gilbert <DavidAGilbert@uk.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/char/sclp_sdias.c

@@ -242,11 +242,13 @@ int sclp_sdias_copy(void *dest, int start_blk, int nr_blks)
 	switch (sdias_evbuf.event_status) {
 		case EVSTATE_ALL_STORED:
 			TRACE("all stored\n");
+			break;
 		case EVSTATE_PART_STORED:
 			TRACE("part stored: %i\n", sdias_evbuf.blk_cnt);
 			break;
 		case EVSTATE_NO_DATA:
 			TRACE("no data\n");
+			/* fall through */
 		default:
 			pr_err("Error from SCLP while copying hsa. "
 			       "Event status = %x\n",