sctp: fix missing label when PROC_FS=n

Fix missing label when CONFIG_PROC_FS=n:

net/sctp/protocol.c: In function 'sctp_proc_init':
net/sctp/protocol.c:106: error: label 'out_nomem' used but not defined
make[3]: *** [net/sctp/protocol.o] Error 1

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>