thermal: shorten too long mcast group name

[ Upstream commits 73214f5d9f33b79918b1f7babddd5c8af28dd23d
  and f1e79e208076ffe7bad97158275f1c572c04f5c7, the latter
  adds an assertion to genetlink to prevent this from happening
  again in the future. ]

The original name is too long.

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/thermal.h

@@ -108,7 +108,7 @@ struct thermal_zone_device {
 /* Adding event notification support elements */
 #define THERMAL_GENL_FAMILY_NAME                "thermal_event"
 #define THERMAL_GENL_VERSION                    0x01
-#define THERMAL_GENL_MCAST_GROUP_NAME           "thermal_mc_group"
+#define THERMAL_GENL_MCAST_GROUP_NAME           "thermal_mc_grp"
 
 enum events {
 	THERMAL_AUX0,

net/netlink/genetlink.c

@@ -142,6 +142,7 @@ int genl_register_mc_group(struct genl_family *family,
 	int err = 0;
 
 	BUG_ON(grp->name[0] == '\0');
+	BUG_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL);
 
 	genl_lock();