dccp: remove unused inline function dccp_set_seqno

There's no callers in-tree since commit 792b48780e8b ("dccp: Implement
both feature-local and feature-remote Sequence Window feature")

Signed-off-by: YueHaibing <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/dccp/dccp.h

···
 #define ADD48(a, b)	 (((a) + (b)) & UINT48_MAX)
 #define SUB48(a, b)	 ADD48((a), COMPLEMENT48(b))
 
-static inline void dccp_set_seqno(u64 *seqno, u64 value)
-{
-	*seqno = value & UINT48_MAX;
-}
-
 static inline void dccp_inc_seqno(u64 *seqno)
 {
 	*seqno = ADD48(*seqno, 1);