ASoC: fsl ssi doc: Remove unused properties

The fsl_ssi driver only checks for the ac97 mode property, so remove the unused
ones.
Suggested-by: Nicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Timur Tabi <timur@tabi.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/fsl,ssi.txt

@@ -58,13 +58,7 @@ Optional properties:
 		    Documentation/devicetree/bindings/dma/dma.txt.
 - dma-names:	    Two dmas have to be defined, "tx" and "rx", if fsl,imx-fiq
 		    is not defined.
-- fsl,mode:         The operating mode for the SSI interface.
-                    "i2s-slave" - I2S mode, SSI is clock slave
-                    "i2s-master" - I2S mode, SSI is clock master
-                    "lj-slave" - left-justified mode, SSI is clock slave
-                    "lj-master" - l.j. mode, SSI is clock master
-                    "rj-slave" - right-justified mode, SSI is clock slave
-                    "rj-master" - r.j., SSI is clock master
+- fsl,mode:         The operating mode for the AC97 interface only.
                     "ac97-slave" - AC97 mode, SSI is clock slave
                     "ac97-master" - AC97 mode, SSI is clock master