ARM: imx6q_logic: Enable DM_SERIAL

In order to call preloader_console_init from board_init_f when
DM_SERIAL is enabled, it neesd to call spl_early_init() to get early access
to DM and device tree.

This patch calls spl_early_init just before preloader_console_init()
and enables DM_SERIAL and SPL_DM_SERIAL.

Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
diff --git a/board/logicpd/imx6/imx6logic.c b/board/logicpd/imx6/imx6logic.c
index 36ebe12..7fb6dc4 100644
--- a/board/logicpd/imx6/imx6logic.c
+++ b/board/logicpd/imx6/imx6logic.c
@@ -348,6 +348,9 @@
 	/* setup GP timer */
 	timer_init();
 
+	/* Enable device tree and early DM support*/
+	spl_early_init();
+
 	/* UART clocks enabled and gd valid - init serial console */
 	preloader_console_init();
 }