doc: Fix typo in doucmentations

Correct typo (double words) in documentations.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/Documentation/filesystems/nfs/pnfs.txt b/Documentation/filesystems/nfs/pnfs.txt
index 52ae07f..adc81a3 100644
--- a/Documentation/filesystems/nfs/pnfs.txt
+++ b/Documentation/filesystems/nfs/pnfs.txt
@@ -12,7 +12,7 @@
 ----------------------
 The on-the-wire command LAYOUTGET corresponds to struct
 pnfs_layout_segment, usually referred to by the variable name lseg.
-Each nfs_inode may hold a pointer to a cache of of these layout
+Each nfs_inode may hold a pointer to a cache of these layout
 segments in nfsi->layout, of type struct pnfs_layout_hdr.
 
 We reference the header for the inode pointing to it, across each