fs: Describe @isnew parameter in ilookup5_nowait()

Sphinx reports kernel-doc warning:

WARNING: ./fs/inode.c:1607 function parameter 'isnew' not described in 'ilookup5_nowait'

Describe the parameter.

Fixes: a27628f ("fs: rework I_NEW handling to operate without fences")
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Link: https://patch.msgid.link/20251219024620.22880-2-bagasdotme@gmail.com
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: bagasme

fs/inode.c

@@ -1593,6 +1593,9 @@ EXPORT_SYMBOL(igrab);
  * @hashval:	hash value (usually inode number) to search for
  * @test:	callback used for comparisons between inodes
  * @data:	opaque data pointer to pass to @test
+ * @isnew:	return argument telling whether I_NEW was set when
+ *		the inode was found in hash (the caller needs to
+ *		wait for I_NEW to clear)
  *
  * Search for the inode specified by @hashval and @data in the inode cache.
  * If the inode is in the cache, the inode is returned with an incremented