dt-bindings: pinctrl: at91: Fix a typo ("descibe")

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Link: https://lore.kernel.org/r/20200308214230.15193-1-j.neuschaefer@gmx.net
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

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

@@ -38,7 +38,7 @@ Bank: 3 (A, B and C)
   0xffffffff 0x7fff3ccf  /* pioB */
   0xffffffff 0x007fffff  /* pioC */
 
-For each peripheral/bank we will descibe in a u32 if a pin can be
+For each peripheral/bank we will describe in a u32 if a pin can be
 configured in it by putting 1 to the pin bit (1 << pin)
 
 Let's take the pioA on peripheral B