pinctrl: remove slew-rate parameter from tz1090

As the binding for slew-rate is under discussion and seems to need
more tought it will get removed for now, so it doesn't get an offical
release.

Therefore remove it again from the only current user, tz1090.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/Documentation/devicetree/bindings/pinctrl/img,tz1090-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/img,tz1090-pinctrl.txt
index 39bfd9c..4b27c99 100644
--- a/Documentation/devicetree/bindings/pinctrl/img,tz1090-pinctrl.txt
+++ b/Documentation/devicetree/bindings/pinctrl/img,tz1090-pinctrl.txt
@@ -44,9 +44,6 @@
   - bias-pull-down
   - input-schmitt-enable
   - input-schmitt-disable
-  - slew-rate: Integer, control slew rate of pins.
-      0: slow (half frequency)
-      1: fast
   - drive-strength: Integer, control drive strength of pins in mA.
       2: 2mA
       4: 4mA
@@ -124,7 +121,6 @@
         function:              afe, ts_out_0.
         input-schmitt-enable:  supported.
         input-schmitt-disable: supported.
-        slew-rate:             supported.
         drive-strength:        supported.
     pdm_d
         pins:                  pdm_d.
@@ -153,12 +149,11 @@
                                lcd_trace, phy_ringosc.
         input-schmitt-enable:  supported.
         input-schmitt-disable: supported.
-        slew-rate:             supported.
         drive-strength:        supported.
 
   drive groups:
 
-    These all support input-schmitt-enable, input-schmitt-disable, slew-rate,
+    These all support input-schmitt-enable, input-schmitt-disable,
     and drive-strength.
 
     jtag