imx: Add support for i.MX28 based XEA board

This patch introduces support for i.MX28 based XEA board.

This board supports DM/DTS in U-Boot proper as well as DM aware drivers
in SPL (u-boot.sb) by using OF_PLATDATA.
More detailed information regarding usage of it can be found in
./board/liebherr/xea/README file.

U-Boot SPL 2019.10-rc1-00233-g6aa549f05c (Aug 12 2019 - 09:23:36 +0200)
Trying to boot from MMC1
MMC0: Command 8 timeout (status 0xf0344020)
mmc_load_image_raw_sector: mmc block read error

U-Boot 2019.10-rc1-00233-g6aa549f05c (Aug 12 2019 - 09:23:36 +0200)

CPU:   Freescale i.MX28 rev1.2 at 454 MHz
BOOT:  SSP SPI #3, master, 3V3 NOR
Model: Liebherr (LWE) XEA i.MX28 Board
DRAM:  128 MiB
MMC:   MXS MMC: 0
Loading Environment from SPI Flash... SF: Detected n25q128a13 with page size 256 Bytes, erase size 64 KiB, total 16 MiB
OK
In:    serial
Out:   serial
Err:   serial
Net:
Warning: ethernet@800f0000 (eth0) using random MAC address - ce:e1:9e:46:f3:a2
eth0: ethernet@800f0000
Hit any key to stop autoboot:  0

Signed-off-by: Lukasz Majewski <lukma@denx.de>
diff --git a/board/liebherr/xea/Makefile b/board/liebherr/xea/Makefile
new file mode 100644
index 0000000..abf5008
--- /dev/null
+++ b/board/liebherr/xea/Makefile
@@ -0,0 +1,12 @@
+#
+# (C) Copyright 2019
+# Lukasz Majewski, DENX Software Engineering, lukma@denx.de.
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+obj-y	:= xea.o
+
+ifdef	CONFIG_SPL_BUILD
+obj-y	+= spl_xea.o
+endif