sctp: remove the typedef sctp_subtype_t

This patch is to remove the typedef sctp_subtype_t, and
replace with union sctp_subtype in the places where it's
using this typedef.

Note that it doesn't fix many indents although it should,
as sctp_disposition_t's removal would mess them up again.
So better to fix them when removing sctp_disposition_t in
later patch.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/primitive.c

@@ -53,7 +53,7 @@
 int sctp_primitive_ ## name(struct net *net, struct sctp_association *asoc, \
 			    void *arg) { \
 	int error = 0; \
-	enum sctp_event event_type; sctp_subtype_t subtype; \
+	enum sctp_event event_type; union sctp_subtype subtype; \
 	enum sctp_state state; \
 	struct sctp_endpoint *ep; \
 	\