dm: test: Add test case for dev->dma_offset

Add test to validate dev->dma_offset is properly set on devices.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Peter Robinson <pbrobinson@gmail.com>
Signed-off-by: Matthias Brugger <mbrugger@suse.com>
diff --git a/configs/sandbox_spl_defconfig b/configs/sandbox_spl_defconfig
index 61dae34..c011870 100644
--- a/configs/sandbox_spl_defconfig
+++ b/configs/sandbox_spl_defconfig
@@ -95,6 +95,7 @@
 CONFIG_NETCONSOLE=y
 CONFIG_IP_DEFRAG=y
 CONFIG_SPL_DM=y
+CONFIG_DM_DMA=y
 CONFIG_REGMAP=y
 CONFIG_SPL_REGMAP=y
 CONFIG_SYSCON=y