fs/direct-io.c: fix kernel-doc warning

Fix kernel-doc warning in fs/direct-io.c:

  fs/direct-io.c:258: warning: Excess function parameter 'offset' description in 'dio_complete'

Also, don't mark this function as having kernel-doc notation since it is
not exported.

Link: http://lkml.kernel.org/r/97908511-4328-4a56-17fe-f43a1d7aa470@infradead.org
Fixes: 6d544bb ("dio: centralize completion in dio_complete()")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Zach Brown <zab@zabbo.net>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/direct-io.c

@@ -241,9 +241,8 @@ void dio_warn_stale_pagecache(struct file *filp)
 	}
 }
 
-/**
+/*
  * dio_complete() - called when all DIO BIO I/O has been completed
- * @offset: the byte offset in the file of the completed operation
  *
  * This drops i_dio_count, lets interested parties know that a DIO operation
  * has completed, and calculates the resulting return code for the operation.