dm: arm: spl: Make driver model linker lists available

The linker lists feature is useful in SPL as it holds the driver model
platform data. So don't throw away the lists.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@ti.com>

arch/arm/cpu/u-boot-spl.lds

@@ -34,6 +34,13 @@ SECTIONS
 	. = ALIGN(4);
 
 	. = .;
+#ifdef CONFIG_SPL_DM
+	.u_boot_list : {
+		KEEP(*(SORT(.u_boot_list_*_driver_*)));
+		KEEP(*(SORT(.u_boot_list_*_uclass_*)));
+	}
+#endif
+	. = ALIGN(4);
 
 	__image_copy_end = .;