dm: core: Allow sequence alias support to be removed for SPL

In many cases SPL only uses a single serial port and there is no need for
alias sequence support. We will just use the serial port pointed to by
stdout-path in the /chosen node.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/config_uncmd_spl.h b/include/config_uncmd_spl.h
index a9106f4..38cb0e8 100644
--- a/include/config_uncmd_spl.h
+++ b/include/config_uncmd_spl.h
@@ -31,6 +31,7 @@
 
 #undef CONFIG_DM_WARN
 #undef CONFIG_DM_DEVICE_REMOVE
+#undef CONFIG_DM_SEQ_ALIAS
 #undef CONFIG_DM_STDIO
 
 #endif /* CONFIG_SPL_BUILD */