pinctrl: pinctrl-imx1-core.c: Cleaning up if unsigned is less than zero

Remove checking if a unsigned is less than zero

This was found using a static code analysis program called cppcheck.
Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/pinctrl-imx1-core.c

@@ -526,7 +526,7 @@ static int imx1_pinctrl_parse_functions(struct device_node *np,
 	/* Initialise function */
 	func->name = np->name;
 	func->num_groups = of_get_child_count(np);
-	if (func->num_groups <= 0)
+	if (func->num_groups == 0)
 		return -EINVAL;
 
 	func->groups = devm_kzalloc(info->dev,