net: kcm: fill in MODULE_DESCRIPTION()

W=1 builds now warn if module is built without a MODULE_DESCRIPTION().

Link: https://lore.kernel.org/r/20231108020305.537293-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/kcm/kcmsock.c

@@ -1946,4 +1946,5 @@ module_init(kcm_init);
 module_exit(kcm_exit);
 
 MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("KCM (Kernel Connection Multiplexor) sockets");
 MODULE_ALIAS_NETPROTO(PF_KCM);