drivers: board: Make the board drivers available in SPL

Make the board driver available in the SPL too. The board driver is a way
to provide useful information about the board and that can be useful in
the SPL too.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/board/Makefile b/drivers/board/Makefile
index c8dab4f..cc16361 100644
--- a/drivers/board/Makefile
+++ b/drivers/board/Makefile
@@ -2,6 +2,6 @@
 #
 # (C) Copyright 2017
 # Mario Six,  Guntermann & Drunck GmbH, mario.six@gdsys.cc
-obj-$(CONFIG_BOARD) += board-uclass.o
+obj-y += board-uclass.o
 obj-$(CONFIG_BOARD_GAZERBEAM) += gazerbeam.o
 obj-$(CONFIG_BOARD_SANDBOX) += sandbox.o