clk: Make clk_free return void

Most callers of this function do not check the return value, and it is
unclear what action they should take if it fails. If a function is freeing
multiple clocks, it should not stop just because the first one failed.
Since the callbacks can no longer fail, just convert the return type to
void.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Link: https://lore.kernel.org/r/20220115222504.617013-8-seanga2@gmail.com
diff --git a/include/clk.h b/include/clk.h
index 23e4d4e..76bb64b 100644
--- a/include/clk.h
+++ b/include/clk.h
@@ -414,9 +414,9 @@
  * @clk:	A clock struct that was previously successfully requested by
  *		clk_request/get_by_*().
  *
- * Return: 0 if OK, or a negative error code.
+ * Free resources allocated by clk_request() (or any clk_get_* function).
  */
-int clk_free(struct clk *clk);
+void clk_free(struct clk *clk);
 
 /**
  * clk_get_rate() - Get current clock rate.
@@ -562,9 +562,9 @@
 	return -ENOSYS;
 }
 
-static inline int clk_free(struct clk *clk)
+static inline void clk_free(struct clk *clk)
 {
-	return 0;
+	return;
 }
 
 static inline ulong clk_get_rate(struct clk *clk)