ARM: at91/at91-pinctrl documentation: fix spelling mistake: "contoller" -> "controller"

trivial fix to spelling mistake in documentation
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Acked-by: NNicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/atmel,at91-pinctrl.txt

@@ -4,7 +4,7 @@ The AT91 Pinmux Controller, enables the IC
 to share one PAD to several functional blocks. The sharing is done by
 multiplexing the PAD input/output signals. For each PAD there are up to
 8 muxing options (called periph modes). Since different modules require
-different PAD settings (like pull up, keeper, etc) the contoller controls
+different PAD settings (like pull up, keeper, etc) the controller controls
 also the PAD settings parameters.
 
 Please refer to pinctrl-bindings.txt in this directory for details of the