omap2/3: Multiboot compile fixes to compile in omap2 and omap3

Allows compiling in omap2 and omap3.

Signed-off-by: Tony Lindgren <tony@atomide.com>
diff --git a/arch/arm/mach-omap2/opp2xxx.h b/arch/arm/mach-omap2/opp2xxx.h
index ed6df04..38b7305 100644
--- a/arch/arm/mach-omap2/opp2xxx.h
+++ b/arch/arm/mach-omap2/opp2xxx.h
@@ -417,7 +417,12 @@
 
 
 extern const struct prcm_config omap2420_rate_table[];
+
+#ifdef CONFIG_ARCH_OMAP2430
 extern const struct prcm_config omap2430_rate_table[];
+#else
+#define omap2430_rate_table	NULL
+#endif
 extern const struct prcm_config *rate_table;
 extern const struct prcm_config *curr_prcm_set;