doc: fix wrong arch/i386 references

Change all "arch/i386" to "arch/x86" in Documentaion/,
since the directory has changed.

Also update the files which have changed their filename
in the meantime accordingly.

Signed-off-by: Wanlong Gao <wanlong.gao@gmail.com>
[jkosina@suse.cz: reword changelog]
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/Documentation/filesystems/nfs/nfsroot.txt b/Documentation/filesystems/nfs/nfsroot.txt
index 90c71c6..ffdd9d8 100644
--- a/Documentation/filesystems/nfs/nfsroot.txt
+++ b/Documentation/filesystems/nfs/nfsroot.txt
@@ -226,7 +226,7 @@
      	cdrecord.
 
 	e.g.
-	  cdrecord dev=ATAPI:1,0,0 arch/i386/boot/image.iso
+	  cdrecord dev=ATAPI:1,0,0 arch/x86/boot/image.iso
 
      	For more information on isolinux, including how to create bootdisks
      	for prebuilt kernels, see http://syslinux.zytor.com/