drm/amd/display: Don't leak dc_stream_state.

Noticed while playing “Valley”, which was causing some 8MB of leakage per
second. kmemleak listed many entries looking like this:

    unreferenced object 0xffff8802c2951800 (size 1024):
      comm "Xorg", pid 2982, jiffies 4297410155 (age 392.787s)
      hex dump (first 32 bytes):
        00 50 f9 0c 04 88 ff ff 98 08 00 00 00 00 00 00  .P..............
        80 07 00 00 00 00 00 00 58 00 00 00 2c 00 00 00  ........X...,...
      backtrace:
        [<ffffffff810cd4c3>] create_object+0x13c/0x261
        [<ffffffff815abdc2>] kmemleak_alloc+0x20/0x3c
        [<ffffffff810cad1d>] slab_post_alloc_hook+0x42/0x52
        [<ffffffff810cb8e0>] kmem_cache_alloc+0x67/0x76
        [<ffffffff813bbb54>] dc_create_stream_for_sink+0x24/0x1cf
        [<ffffffff81373aaa>] create_stream_for_sink+0x6f/0x295
        [<ffffffff81373dc2>] dm_update_crtcs_state+0xa6/0x268
        [<ffffffff8137401e>] amdgpu_dm_atomic_check+0x9a/0x314
        [<ffffffff812ac3dd>] drm_atomic_check_only+0x17a/0x42d
        [<ffffffff812ac6a3>] drm_atomic_commit+0x13/0x4b
        [<ffffffff812ad1a5>] drm_atomic_connector_commit_dpms+0xcb/0xe8
        [<ffffffff812b1238>] drm_mode_obj_set_property_ioctl+0xe6/0x1e3
        [<ffffffff812b027b>] drm_mode_connector_property_set_ioctl+0x2b/0x2d
        [<ffffffff8129f427>] drm_ioctl_kernel+0x64/0x9d
        [<ffffffff8129f6a2>] drm_ioctl+0x230/0x316
        [<ffffffff812ca4d3>] amdgpu_drm_ioctl+0x4b/0x7d

v2: also handle break statements.
Signed-off-by: Darren Salt <devspam@moreofthesa.me.uk>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -4357,6 +4357,7 @@ static int dm_update_crtcs_state(
 	int i;
 	struct dm_crtc_state *old_acrtc_state, *new_acrtc_state;
 	struct dm_atomic_state *dm_state = to_dm_atomic_state(state);
+	struct dc_stream_state *new_stream;
 	int ret = 0;
 
 	/*TODO Move this code into dm_crtc_atomic_check once we get rid of dc_validation_set */
@@ -4364,10 +4365,11 @@ static int dm_update_crtcs_state(
 	for_each_crtc_in_state(state, crtc, crtc_state, i) {
 		struct amdgpu_crtc *acrtc = NULL;
 		struct amdgpu_connector *aconnector = NULL;
-		struct dc_stream_state *new_stream = NULL;
 		struct drm_connector_state *conn_state = NULL;
 		struct dm_connector_state *dm_conn_state = NULL;
 
+		new_stream = NULL;
+
 		old_acrtc_state = to_dm_crtc_state(crtc->state);
 		new_acrtc_state = to_dm_crtc_state(crtc_state);
 		acrtc = to_amdgpu_crtc(crtc);
@@ -4415,7 +4417,7 @@ static int dm_update_crtcs_state(
 
 
 		if (!drm_atomic_crtc_needs_modeset(crtc_state))
-				continue;
+			goto next_crtc;
 
 		DRM_DEBUG_KMS(
 			"amdgpu_crtc id:%d crtc_state_flags: enable:%d, active:%d, "
@@ -4433,7 +4435,7 @@ static int dm_update_crtcs_state(
 		if (!enable) {
 
 			if (!old_acrtc_state->stream)
-				continue;
+				goto next_crtc;
 
 			DRM_DEBUG_KMS("Disabling DRM crtc: %d\n",
 					crtc->base.id);
@@ -4444,7 +4446,7 @@ static int dm_update_crtcs_state(
 					dm_state->context,
 					old_acrtc_state->stream)) {
 				ret = -EINVAL;
-				break;
+				goto fail;
 			}
 
 			dc_stream_release(old_acrtc_state->stream);
@@ -4455,7 +4457,7 @@ static int dm_update_crtcs_state(
 		} else {/* Add stream for any updated/enabled CRTC */
 
 			if (modereset_required(crtc_state))
-				continue;
+				goto next_crtc;
 
 			if (modeset_required(crtc_state, new_stream,
 					     old_acrtc_state->stream)) {
@@ -4473,19 +4475,25 @@ static int dm_update_crtcs_state(
 						dm_state->context,
 						new_acrtc_state->stream)) {
 					ret = -EINVAL;
-					break;
+					goto fail;
 				}
 
 				*lock_and_validation_needed = true;
 			}
 		}
 
+next_crtc:
 		/* Release extra reference */
 		if (new_stream)
 			 dc_stream_release(new_stream);
 	}
 
 	return ret;
+
+fail:
+	if (new_stream)
+		dc_stream_release(new_stream);
+	return ret;
 }
 
 static int dm_update_planes_state(