proc: introduce proc_create_net{,_data}

Variants of proc_create{,_data} that directly take a struct seq_operations
and deal with network namespaces in ->open and ->release.  All callers of
proc_create + seq_open_net converted over, and seq_{open,release}_net are
removed entirely.

Signed-off-by: Christoph Hellwig <hch@lst.de>
diff --git a/include/net/udp.h b/include/net/udp.h
index 093cd323..621778b 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -423,8 +423,8 @@ void *udp_seq_start(struct seq_file *seq, loff_t *pos);
 void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos);
 void udp_seq_stop(struct seq_file *seq, void *v);
 
-extern const struct file_operations udp_afinfo_seq_fops;
-extern const struct file_operations udp6_afinfo_seq_fops;
+extern const struct seq_operations udp_seq_ops;
+extern const struct seq_operations udp6_seq_ops;
 
 int udp4_proc_init(void);
 void udp4_proc_exit(void);