scsi: aha1740: Fix fall-through warnings for Clang

In preparation to enable -Wimplicit-fallthrough for Clang, fix a warning by
explicitly adding a break statement instead of letting the code fall
through to the next case.

Link: https://github.com/KSPP/linux/issues/115
Link: https://lore.kernel.org/r/e9fc10eb7d843e6f31e50400d428bd7a217684ac.1605896060.git.gustavoars@kernel.orgSigned-off-by: NGustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/aha1740.c

@@ -152,6 +152,7 @@ static int aha1740_makecode(unchar *sense, unchar *status)
 					retval=DID_ERROR; /* It's an Overrun */
 				/* If not overrun, assume underrun and
 				 * ignore it! */
+				break;
 			case 0x00: /* No info, assume no error, should
 				    * not occur */
 				break;