proc: introduce proc_create_seq{,_data}

Variants of proc_create{,_data} that directly take a struct seq_operations
argument and drastically reduces the boilerplate code in the callers.

All trivial callers converted over.

Signed-off-by: Christoph Hellwig <hch@lst.de>

fs/proc/internal.h

@@ -44,6 +44,7 @@ struct proc_dir_entry {
 	struct completion *pde_unload_completion;
 	const struct inode_operations *proc_iops;
 	const struct file_operations *proc_fops;
+	const struct seq_operations *seq_ops;
 	void *data;
 	unsigned int low_ino;
 	nlink_t nlink;