docs/pinctrl: fix typo in mapping example

Small typo. The device name in the example should be "foo-i2c.0" and
not "foo-i2c.o".
Signed-off-by: Marc Ferland <marc.ferland@sonatest.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240709183919.3337131-1-marc.ferland@sonatest.com

Documentation/driver-api/pin-control.rst

@@ -1002,7 +1002,7 @@ it even more compact which assumes you want to use pinctrl-foo and position
 .. code-block:: c
 
 	static struct pinctrl_map mapping[] __initdata = {
-		PIN_MAP_MUX_GROUP("foo-i2c.o", PINCTRL_STATE_DEFAULT,
+		PIN_MAP_MUX_GROUP("foo-i2c.0", PINCTRL_STATE_DEFAULT,
 				  "pinctrl-foo", NULL, "i2c0"),
 	};