pinctrl: single: fix DT bindings documentation

Remove extra comma in pinctrl-single documentation.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --cc Documentation/devicetree/bindings/pinctrl/pinctrl-single.txt
Simple merge