ARM: DRA7: PRM: add voltage processor check behind a prm_feature flag

This is done in attempt to get rid of cpu_is_X calls from the PRM core.
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Acked-by: Paul Walmsley <paul@pwsan.com>
Tested-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/prm.h

@@ -29,6 +29,7 @@ int of_prcm_init(void);
  * PRM_HAS_VOLTAGE: has voltage domains
  */
 #define PRM_HAS_IO_WAKEUP	(1 << 0)
+#define PRM_HAS_VOLTAGE		(1 << 1)
 
 /*
  * MAX_MODULE_SOFTRESET_WAIT: Maximum microseconds to wait for OMAP

arch/arm/mach-omap2/prm44xx.c

@@ -652,11 +652,10 @@ static int omap4_pwrdm_wait_transition(struct powerdomain *pwrdm)
 
 static int omap4_check_vcvp(void)
 {
-	/* No VC/VP on dra7xx devices */
-	if (soc_is_dra7xx())
-		return 0;
+	if (prm_features & PRM_HAS_VOLTAGE)
+		return 1;
 
-	return 1;
+	return 0;
 }
 
 struct pwrdm_ops omap4_pwrdm_operations = {
@@ -696,6 +695,9 @@ int __init omap44xx_prm_init(void)
 	if (cpu_is_omap44xx() || soc_is_omap54xx() || soc_is_dra7xx())
 		prm_features |= PRM_HAS_IO_WAKEUP;
 
+	if (!soc_is_dra7xx())
+		prm_features |= PRM_HAS_VOLTAGE;
+
 	return prm_register(&omap44xx_prm_ll_data);
 }