PM / clk: Add support for adding a specific clock from device-tree

Some drivers using the PM clocks framework need to add specific clocks
from device-tree using a name by calling the functions
of_clk_get_by_name() and then pm_clk_add_clk(). Rather than having
drivers call both functions, add a helper function of_pm_clk_add_clk()
that will call these functions so drivers can call a single function
to add a specific clock from device-tree.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/include/linux/pm_clock.h b/include/linux/pm_clock.h
index 308d604..09779b0 100644
--- a/include/linux/pm_clock.h
+++ b/include/linux/pm_clock.h
@@ -42,6 +42,7 @@
 extern void pm_clk_destroy(struct device *dev);
 extern int pm_clk_add(struct device *dev, const char *con_id);
 extern int pm_clk_add_clk(struct device *dev, struct clk *clk);
+extern int of_pm_clk_add_clk(struct device *dev, const char *name);
 extern int of_pm_clk_add_clks(struct device *dev);
 extern void pm_clk_remove(struct device *dev, const char *con_id);
 extern void pm_clk_remove_clk(struct device *dev, struct clk *clk);