Documentation: dt: opp: fix spelling mistake

Signed-off-by: NEric Engestrom <eric@engestrom.ch>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRob Herring <robh@kernel.org>

Documentation/devicetree/bindings/opp/opp.txt

@@ -45,7 +45,7 @@ Devices supporting OPPs must set their "operating-points-v2" property with
 phandle to a OPP table in their DT node. The OPP core will use this phandle to
 find the operating points for the device.
 
-If required, this can be extended for SoC vendor specfic bindings. Such bindings
+If required, this can be extended for SoC vendor specific bindings. Such bindings
 should be documented as Documentation/devicetree/bindings/power/<vendor>-opp.txt
 and should have a compatible description like: "operating-points-v2-<vendor>".