clk: Replace of_clk_get_by_clkspec() with of_clk_get_from_provider()

of_clk_get_by_clkspec() has the same function signature as
of_clk_get_from_provider()

 struct clk *of_clk_get_by_clkspec(struct of_phandle_args
 *clkspec)
 struct clk *of_clk_get_from_provider(struct of_phandle_args
 *clkspec)

except of_clk_get_by_clkspec() checks to make sure clkspec is not
NULL. Let's remove of_clk_get_by_clkspec() and replace the
callers of it (clkconf.c) with of_clk_get_from_provider().

Cc: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/clk.c

@@ -2857,17 +2857,6 @@ static const struct of_device_id __clk_of_table_sentinel
 static LIST_HEAD(of_clk_providers);
 static DEFINE_MUTEX(of_clk_mutex);
 
-/* of_clk_provider list locking helpers */
-void of_clk_lock(void)
-{
-	mutex_lock(&of_clk_mutex);
-}
-
-void of_clk_unlock(void)
-{
-	mutex_unlock(&of_clk_mutex);
-}
-
 struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
 				     void *data)
 {
@@ -2951,7 +2940,11 @@ struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec,
 	struct of_clk_provider *provider;
 	struct clk *clk = ERR_PTR(-EPROBE_DEFER);
 
+	if (!clkspec)
+		return ERR_PTR(-EINVAL);
+
 	/* Check if we have such a provider in our array */
+	mutex_lock(&of_clk_mutex);
 	list_for_each_entry(provider, &of_clk_providers, link) {
 		if (provider->node == clkspec->np)
 			clk = provider->get(clkspec, provider->data);
@@ -2967,19 +2960,22 @@ struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec,
 			break;
 		}
 	}
+	mutex_unlock(&of_clk_mutex);
 
 	return clk;
 }
 
+/**
+ * of_clk_get_from_provider() - Lookup a clock from a clock provider
+ * @clkspec: pointer to a clock specifier data structure
+ *
+ * This function looks up a struct clk from the registered list of clock
+ * providers, an input is a clock specifier data structure as returned
+ * from the of_parse_phandle_with_args() function call.
+ */
 struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
 {
-	struct clk *clk;
-
-	mutex_lock(&of_clk_mutex);
-	clk = __of_clk_get_from_provider(clkspec, NULL, __func__);
-	mutex_unlock(&of_clk_mutex);
-
-	return clk;
+	return __of_clk_get_from_provider(clkspec, NULL, __func__);
 }
 
 int of_clk_get_parent_count(struct device_node *np)