powercap/dtpm: Fixup kfree for virtual node

When the node is virtual there is no release function associated which
can free the memory.

Free the memory when no 'ops' exists.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20220130210210.549877-3-daniel.lezcano@linaro.org

drivers/powercap/dtpm.c

@@ -181,12 +181,12 @@ int dtpm_release_zone(struct powercap_zone *pcz)
 
 	if (dtpm->ops)
 		dtpm->ops->release(dtpm);
+	else
+		kfree(dtpm);
 
 	if (root == dtpm)
 		root = NULL;
 
-	kfree(dtpm);
-
 	return 0;
 }