pinctrl: get_group_pins() const fixes

get_group_pins() "returns" a pointer to an array of const objects, through
a pointer parameter. Fix the prototype so what's pointed at by the returned
pointer is const, rather than the function parameter being const.

This also allows the removal of a cast in each of the two current pinmux
drivers.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

include/linux/pinctrl/pinctrl.h

@@ -75,8 +75,8 @@ struct pinctrl_ops {
 				       unsigned selector);
 	int (*get_group_pins) (struct pinctrl_dev *pctldev,
 			       unsigned selector,
-			       unsigned ** const pins,
-			       unsigned * const num_pins);
+			       const unsigned **pins,
+			       unsigned *num_pins);
 	void (*pin_dbg_show) (struct pinctrl_dev *pctldev, struct seq_file *s,
 			  unsigned offset);
 };