xfs: Remove the description of nodelaylog mount option from xfs.txt

nodelaylog mount option is removed by commit 93b8a585. But there still be
the description about it in the xfs document. This patch removes it.

Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

Documentation/filesystems/xfs.txt

@@ -43,7 +43,7 @@ When mounting an XFS filesystem, the following options are accepted.
 	Issue command to let the block device reclaim space freed by the
 	filesystem.  This is useful for SSD devices, thinly provisioned
 	LUNs and virtual machine images, but may have a performance
-	impact.  This option is incompatible with the nodelaylog option.
+	impact.
 
   dmapi
 	Enable the DMAPI (Data Management API) event callouts.