pinctrl: single: fix freudian slip

commit 03e9f0cac5da6af85758276cb4624caf5911f2b9
"pinctrl: clean up after enable refactoring"
renamed the vtable callback .enable to .set_mux. The
renaming was done manually, and one of the alterations
contained a freudian slip. I confess, I am human.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/pinctrl/pinctrl-single.c b/drivers/pinctrl/pinctrl-single.c
index 9032422..fb94b77 100644
--- a/drivers/pinctrl/pinctrl-single.c
+++ b/drivers/pinctrl/pinctrl-single.c
@@ -519,7 +519,7 @@
 	.get_functions_count = pcs_get_functions_count,
 	.get_function_name = pcs_get_function_name,
 	.get_function_groups = pcs_get_function_groups,
-	.set_mux = pcs_sex_mux,
+	.set_mux = pcs_set_mux,
 	.gpio_request_enable = pcs_request_gpio,
 };