opp: Return genpd virtual devices from dev_pm_opp_attach_genpd()

The cpufreq drivers don't need to do runtime PM operations on the
virtual devices returned by dev_pm_domain_attach_by_name() and so the
virtual devices weren't shared with the callers of
dev_pm_opp_attach_genpd() earlier.

But the IO device drivers would want to do that. This patch updates the
prototype of dev_pm_opp_attach_genpd() to accept another argument to
return the pointer to the array of genpd virtual devices.

Reported-by: Rajendra Nayak <rnayak@codeaurora.org>
Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 08b830f..bdb4358 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -1771,6 +1771,7 @@ static void _opp_detach_genpd(struct opp_table *opp_table)
  * dev_pm_opp_attach_genpd - Attach genpd(s) for the device and save virtual device pointer
  * @dev: Consumer device for which the genpd is getting attached.
  * @names: Null terminated array of pointers containing names of genpd to attach.
+ * @virt_devs: Pointer to return the array of virtual devices.
  *
  * Multiple generic power domains for a device are supported with the help of
  * virtual genpd devices, which are created for each consumer device - genpd
@@ -1788,7 +1789,8 @@ static void _opp_detach_genpd(struct opp_table *opp_table)
  * The order of entries in the names array must match the order in which
  * "required-opps" are added in DT.
  */
-struct opp_table *dev_pm_opp_attach_genpd(struct device *dev, const char **names)
+struct opp_table *dev_pm_opp_attach_genpd(struct device *dev,
+		const char **names, struct device ***virt_devs)
 {
 	struct opp_table *opp_table;
 	struct device *virt_dev;
@@ -1842,6 +1844,8 @@ struct opp_table *dev_pm_opp_attach_genpd(struct device *dev, const char **names
 		name++;
 	}
 
+	if (virt_devs)
+		*virt_devs = opp_table->genpd_virt_devs;
 	mutex_unlock(&opp_table->genpd_virt_dev_lock);
 
 	return opp_table;