omap: opp: add OMAP3 OPP table data and common init

Add OPP data for OMAP34xx and OMAP36xx and initialization functions
to populate OPP tables based on current SoC.
introduce an OMAP generic opp initialization routine which OMAP3
and OMAP4+ SoCs can use to register their OPP definitions.

Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
diff --git a/arch/arm/mach-omap2/pm.h b/arch/arm/mach-omap2/pm.h
index 0d75bfd..2031f15 100644
--- a/arch/arm/mach-omap2/pm.h
+++ b/arch/arm/mach-omap2/pm.h
@@ -20,6 +20,15 @@
 extern int omap_set_pwrdm_state(struct powerdomain *pwrdm, u32 state);
 extern int omap3_idle_init(void);
 
+#if defined(CONFIG_PM_OPP)
+extern int omap3_opp_init(void);
+#else
+static inline int omap3_opp_init(void)
+{
+	return -EINVAL;
+}
+#endif
+
 struct cpuidle_params {
 	u8  valid;
 	u32 sleep_latency;