pinctrl/nomadik: add device tree bindings for db8540

This adds a simple device tree binding for db8540 boards.

Signed-off-by: Gabriel Fernandez <[e-mail]>
Reviewed-by: Philippe Langlais <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>

drivers/pinctrl/pinctrl-nomadik.c

···
 		.compatible = "stericsson,nmk-pinctrl",
 		.data = (void *)PINCTRL_NMK_DB8500,
 	},
+	{
+		.compatible = "stericsson,nmk-pinctrl-db8540",
+		.data = (void *)PINCTRL_NMK_DB8540,
+	},
 	{},
 };