OMAP3+: VC: use last nominal voltage setting to get current_vsel

Instead of reading current vsel value from the VP's voltage register,
just use current nominal voltage translated into vsel via the PMIC.

Doing this allows VC bypass scaling to work even without a VP configured.
Signed-off-by: Kevin Hilman <khilman@ti.com>

arch/arm/mach-omap2/vc.c

@@ -138,7 +138,7 @@ int omap_vc_pre_scale(struct voltagedomain *voltdm,
 		volt_data = NULL;
 
 	*target_vsel = voltdm->pmic->uv_to_vsel(target_volt);
-	*current_vsel = voltdm->read(vdd->vp_data->voltage);
+	*current_vsel = voltdm->pmic->uv_to_vsel(vdd->curr_volt);
 
 	/* Setting the ON voltage to the new target voltage */
 	vc_cmdval = voltdm->read(vc->cmdval_reg);