pinctrl: fix some pinmux typos

Fix some pinmux typos so implementing pinmux drivers
is a bit easier.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/Documentation/pinctrl.txt b/Documentation/pinctrl.txt
index 5324d31..150fd38 100644
--- a/Documentation/pinctrl.txt
+++ b/Documentation/pinctrl.txt
@@ -1024,7 +1024,7 @@
 
 foo_switch()
 {
-	struct pinmux pmx;
+	struct pinmux *pmx;
 
 	/* Enable on position A */
 	pmx = pinmux_get(&device, "spi0-pos-A");