test: Use a local variable for test state

At present we use a global test state for all driver-model tests. Make use
of a local struct like we do with the other tests.

To make this work, add functions to get and set this state. When a test
starts, the state is set (so it can be used in the test). When a test
finishes, the state is unset, so it cannot be used by mistake.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/test/dm/test-uclass.c b/test/dm/test-uclass.c
index f4b540c..0677017 100644
--- a/test/dm/test-uclass.c
+++ b/test/dm/test-uclass.c
@@ -17,8 +17,6 @@
 #include <test/test.h>
 #include <test/ut.h>
 
-static struct unit_test_state *uts = &global_dm_test_state;
-
 int test_ping(struct udevice *dev, int pingval, int *pingret)
 {
 	const struct test_ops *ops = device_get_ops(dev);
@@ -31,6 +29,7 @@
 
 static int test_post_bind(struct udevice *dev)
 {
+	struct unit_test_state *uts = test_get_state();
 	struct dm_test_perdev_uc_pdata *uc_pdata;
 
 	dm_testdrv_op_count[DM_TEST_OP_POST_BIND]++;
@@ -56,6 +55,7 @@
 static int test_pre_probe(struct udevice *dev)
 {
 	struct dm_test_uclass_perdev_priv *priv = dev_get_uclass_priv(dev);
+	struct unit_test_state *uts = test_get_state();
 
 	dm_testdrv_op_count[DM_TEST_OP_PRE_PROBE]++;
 	ut_assert(priv);
@@ -66,6 +66,7 @@
 
 static int test_post_probe(struct udevice *dev)
 {
+	struct unit_test_state *uts = test_get_state();
 	struct udevice *prev = list_entry(dev->uclass_node.prev,
 					    struct udevice, uclass_node);
 
@@ -100,6 +101,8 @@
 
 static int test_init(struct uclass *uc)
 {
+	struct unit_test_state *uts = test_get_state();
+
 	dm_testdrv_op_count[DM_TEST_OP_INIT]++;
 	ut_assert(uclass_get_priv(uc));