radeon: Pass radeon_bo_open flags to the DRM_RADEON_GEM_CREATE ioctl

Not doing so makes it impossible for radeon_bo_open callers to set any
RADEON_GEM_* flags for the newly created BO.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>

radeon/radeon_bo_gem.c

@@ -103,7 +103,7 @@ static struct radeon_bo *bo_open(struct radeon_bo_manager *bom,
         args.size = size;
         args.alignment = alignment;
         args.initial_domain = bo->base.domains;
-        args.flags = 0;
+        args.flags = flags;
         args.handle = 0;
         r = drmCommandWriteRead(bom->fd, DRM_RADEON_GEM_CREATE,
                                 &args, sizeof(args));