sh: extend clock struct with mapped_reg member

Add a "mapped_reg" member to struct clk and use that
to keep the ioremapped register based on enable_reg.

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

include/linux/sh_clk.h

@@ -49,6 +49,7 @@ struct clk {
 
 	void __iomem		*enable_reg;
 	unsigned int		enable_bit;
+	void __iomem		*mapped_reg;
 
 	unsigned long		arch_flags;
 	void			*priv;