Revert "spi: atmel: Drop non-dm code"

As we aren't quite able to convert some platforms with a very small size
limit in SPL yet, we need to revert this for now.

This reverts commit 7b0947787358c6b277431d6b76ce043d8bec641d.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/scripts/config_whitelist.txt b/scripts/config_whitelist.txt
index e549708..997ef77 100644
--- a/scripts/config_whitelist.txt
+++ b/scripts/config_whitelist.txt
@@ -103,6 +103,7 @@
 CONFIG_ATMEL_MCI_8BIT
 CONFIG_ATMEL_NAND_HWECC
 CONFIG_ATMEL_NAND_HW_PMECC
+CONFIG_ATMEL_SPI0
 CONFIG_AT_TRANS
 CONFIG_AUTO_ZRELADDR
 CONFIG_BACKSIDE_L2_CACHE