isdn/gigaset: missing break in do_facility_req

If we take the unsupported supplementary service notification mask
path, we end up falling through and overwriting the error code.
Insert a break statement to skip the remainder of the switch case
and proceed to sending the reply message.

Spotted with Coverity.

Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/isdn/gigaset/capi.c b/drivers/isdn/gigaset/capi.c
index 3286903..a2eabe9 100644
--- a/drivers/isdn/gigaset/capi.c
+++ b/drivers/isdn/gigaset/capi.c
@@ -1180,6 +1180,7 @@
 				confparam[3] = 2;	/* length */
 				capimsg_setu16(confparam, 4,
 					       CapiSupplementaryServiceNotSupported);
+				break;
 			}
 			info = CapiSuccess;
 			confparam[3] = 2;	/* length */