clk: Make clk input parameter of __clk_get_name() const

When calling __clk_get_name() on a const clock:

    warning: passing argument 1 of '__clk_get_name' discards 'const' qualifier from pointer target type
    include/linux/clk-provider.h:613:13: note: expected 'struct clk *' but argument is of type 'const struct clk *'

__clk_get_name() does not modify the passed clock, hence make it const.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/clk.c

@@ -272,7 +272,7 @@ late_initcall_sync(clk_disable_unused);
 
 /***    helper functions   ***/
 
-const char *__clk_get_name(struct clk *clk)
+const char *__clk_get_name(const struct clk *clk)
 {
 	return !clk ? NULL : clk->core->name;
 }

include/linux/clk-provider.h

@@ -607,7 +607,7 @@ void clk_unregister(struct clk *clk);
 void devm_clk_unregister(struct device *dev, struct clk *clk);
 
 /* helper functions */
-const char *__clk_get_name(struct clk *clk);
+const char *__clk_get_name(const struct clk *clk);
 const char *clk_hw_get_name(const struct clk_hw *hw);
 struct clk_hw *__clk_get_hw(struct clk *clk);
 unsigned int clk_hw_get_num_parents(const struct clk_hw *hw);