opp: Reuse the enabled flag in !target_freq path

The OPP core needs to track if the resources of devices are
enabled/configured or not, as it disables the resources when target_freq
is set to 0.

Handle that with the new enabled flag and remove otherwise complex
conditional statements.
Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

drivers/opp/core.c

@@ -886,22 +886,18 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 	}
 
 	if (unlikely(!target_freq)) {
+		ret = 0;
+
+		if (!opp_table->enabled)
+			goto put_opp_table;
+
 		/*
 		 * Some drivers need to support cases where some platforms may
 		 * have OPP table for the device, while others don't and
 		 * opp_set_rate() just needs to behave like clk_set_rate().
 		 */
-		if (!_get_opp_count(opp_table)) {
-			ret = 0;
+		if (!_get_opp_count(opp_table))
 			goto put_opp_table;
-		}
-
-		if (!opp_table->required_opp_tables && !opp_table->regulators &&
-		    !opp_table->paths) {
-			dev_err(dev, "target frequency can't be 0\n");
-			ret = -EINVAL;
-			goto put_opp_table;
-		}
 
 		ret = _set_opp_bw(opp_table, NULL, dev, true);
 		if (ret)
@@ -931,15 +927,12 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 	old_freq = clk_get_rate(clk);
 
 	/* Return early if nothing to do */
-	if (old_freq == freq) {
-		if (!opp_table->required_opp_tables && !opp_table->regulators &&
-		    !opp_table->paths) {
+	if (opp_table->enabled && old_freq == freq) {
 		dev_dbg(dev, "%s: old/new frequencies (%lu Hz) are same, nothing to do\n",
 			__func__, freq);
 		ret = 0;
 		goto put_opp_table;
 	}
-	}
 
 	/*
 	 * For IO devices which require an OPP on some platforms/SoCs