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>
diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h
index 500650f..53cfd0b 100644
--- a/fs/fscache/internal.h
+++ b/fs/fscache/internal.h
@@ -31,6 +31,7 @@
 #include <linux/fscache-cache.h>
 #include <trace/events/fscache.h>
 #include <linux/sched.h>
+#include <linux/seq_file.h>
 
 #define FSCACHE_MIN_THREADS	4
 #define FSCACHE_MAX_THREADS	32
@@ -84,7 +85,7 @@
 	atomic_inc(&histogram[jif]);
 }
 
-extern const struct file_operations fscache_histogram_fops;
+extern const struct seq_operations fscache_histogram_ops;
 
 #else
 #define fscache_hist(hist, start_jif) do {} while (0)