lib/genalloc: fix device leak in of_gen_pool_get()

Make sure to drop the reference taken when looking up the genpool platform
device in of_gen_pool_get() before returning the pool.

Note that holding a reference to a device does typically not prevent its
devres managed resources from being released so there is no point in
keeping the reference.

Link: https://lkml.kernel.org/r/[e-mail]
Fixes: 9375db07adea ("genalloc: add devres support, allow to find a managed pool by device")
Signed-off-by: Johan Hovold <[e-mail]>
Cc: Philipp Zabel <[e-mail]>
Cc: Vladimir Zapolskiy <[e-mail]>
Cc: <[e-mail]> [3.10+]
Signed-off-by: Andrew Morton <[e-mail]>

lib/genalloc.c

···
 		if (!name)
 			name = of_node_full_name(np_pool);
 	}
-	if (pdev)
+	if (pdev) {
 		pool = gen_pool_get(&pdev->dev, name);
+		put_device(&pdev->dev);
+	}
+
 	of_node_put(np_pool);
 
 	return pool;