dt-bindings: mfd: Fix typo in file name of twl-familly.txt

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/input/twl4030-pwrbutton.txt

 Texas Instruments TWL family (twl4030) pwrbutton module
 
 This module is part of the TWL4030. For more details about the whole
-chip see Documentation/devicetree/bindings/mfd/twl-familly.txt.
+chip see Documentation/devicetree/bindings/mfd/twl-family.txt.
 
 This module provides a simple power button event via an Interrupt.