clk: Add __clk_hw_set_clk helper function

After the clk API change to return a per-user clock instance, both the
struct clk_core and struct clk pointers from the hw clock needs to be
assigned to clock that share the same state.

In the future the struct clk_core will be removed and this is going to
change again so to avoid having to change the assignments twice in all
the drivers, add a helper function to have an indirection level.

Signed-off-by: Javier Martinez Canillas <[e-mail]>
Reviewed-by: Stephen Boyd <[e-mail]>
Signed-off-by: Michael Turquette <[e-mail]>

include/linux/clk-provider.h

···
 			      unsigned long *best_parent_rate,
 			      struct clk_hw **best_parent_p);
 
+static inline void __clk_hw_set_clk(struct clk_hw *dst, struct clk_hw *src)
+{
+	dst->clk = src->clk;
+	dst->core = src->core;
+}
+
 /*
  * FIXME clock api without lock protection
  */