clk: Add {devm_}clk_hw_{register,unregister}() APIs

We've largely split the clk consumer and provider APIs along
struct clk and struct clk_hw, but clk_register() still returns a
struct clk pointer for each struct clk_hw that's registered.
Eventually we'd like to only allocate struct clks when there's a
user, because struct clk is per-user now, so clk_register() needs
to change.

Let's add new APIs to register struct clk_hws, but this time
we'll hide the struct clk from the caller by returning an int
error code. Also add an unregistration API that takes the clk_hw
structure that was passed to the registration API. This way
provider drivers never have to deal with a struct clk pointer
unless they're using the clk consumer APIs.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

include/linux/clk-provider.h

@@ -655,9 +655,15 @@ struct clk *clk_register_gpio_mux(struct device *dev, const char *name,
 struct clk *clk_register(struct device *dev, struct clk_hw *hw);
 struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw);
 
+int __must_check clk_hw_register(struct device *dev, struct clk_hw *hw);
+int __must_check devm_clk_hw_register(struct device *dev, struct clk_hw *hw);
+
 void clk_unregister(struct clk *clk);
 void devm_clk_unregister(struct device *dev, struct clk *clk);
 
+void clk_hw_unregister(struct clk_hw *hw);
+void devm_clk_hw_unregister(struct device *dev, struct clk_hw *hw);
+
 /* helper functions */
 const char *__clk_get_name(const struct clk *clk);
 const char *clk_hw_get_name(const struct clk_hw *hw);