Fix omap2430 clock build error

This fixes a build error for 2430.  fixed_div is under a 2420 only define and it should be OMAP2.
Signed-off-by: Richard Woodruff <r-woodruff2@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

include/asm-arm/arch-omap/clock.h

@@ -34,7 +34,7 @@ struct clk {
 	void			(*init)(struct clk *);
 	int			(*enable)(struct clk *);
 	void			(*disable)(struct clk *);
-#if defined(CONFIG_ARCH_OMAP2420)
+#if defined(CONFIG_ARCH_OMAP2)
 	u8			fixed_div;
 #endif
 };