test: gpio: Add tests for the managed API

Add a test to verify that GPIOs can be acquired/released using the managed
API. Also check that the GPIOs are released when the consumer device is
removed.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
diff --git a/test/dm/bus.c b/test/dm/bus.c
index 865e8bd..27b7266 100644
--- a/test/dm/bus.c
+++ b/test/dm/bus.c
@@ -120,7 +120,7 @@
 /* Test that we can probe for children */
 static int dm_test_bus_children(struct unit_test_state *uts)
 {
-	int num_devices = 8;
+	int num_devices = 9;
 	struct udevice *bus;
 	struct uclass *uc;