radv: add the custom border color BO to the list of buffers

The buffer was never added to the list of buffers. This might lead to
VM faults and GPU hangs.

Found this by luck.

Fixes: 57e796a12a8 ("radv: Implement VK_EXT_custom_border_color")
Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5884>
diff --git a/src/amd/vulkan/radv_device.c b/src/amd/vulkan/radv_device.c
index dee12f9..9fc0668 100644
--- a/src/amd/vulkan/radv_device.c
+++ b/src/amd/vulkan/radv_device.c
@@ -3591,6 +3591,10 @@
 		if (queue->device->trace_bo)
 			radv_cs_add_buffer(queue->device->ws, cs, queue->device->trace_bo);
 
+		if (queue->device->border_color_data.bo)
+			radv_cs_add_buffer(queue->device->ws, cs,
+					   queue->device->border_color_data.bo);
+
 		if (i == 0) {
 			si_cs_emit_cache_flush(cs,
 			                       queue->device->physical_device->rad_info.chip_class,