imx: imx7ulp: add EVK board support

Add EVK board support.
Add the evk dts file.

LOG:
U-Boot 2017.03-rc2-00038-gab86c1d (Feb 22 2017 - 15:59:58 +0800)

CPU:   Freescale i.MX7ULP rev1.0 at 500 MHz
Reset cause: POR
Boot mode: Dual boot
Model: NXP i.MX7ULP EVK
DRAM:  1 GiB
MMC:   FSL_SDHC: 0
In:    serial@402D0000
Out:   serial@402D0000
Err:   serial@402D0000
Net:   Net Initialization Skipped
No ethernet found.
Hit any key to stop autoboot:  0

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Cc: Stefano Babic <sbabic@denx.de>
diff --git a/arch/arm/dts/Makefile b/arch/arm/dts/Makefile
index 231ebfa..7be5c02 100644
--- a/arch/arm/dts/Makefile
+++ b/arch/arm/dts/Makefile
@@ -320,6 +320,8 @@
 
 dtb-$(CONFIG_MX7) += imx7-colibri.dtb
 
+dtb-$(CONFIG_ARCH_MX7ULP) += imx7ulp-evk.dtb
+
 dtb-$(CONFIG_SOC_KEYSTONE) += keystone-k2hk-evm.dtb \
 	keystone-k2l-evm.dtb \
 	keystone-k2e-evm.dtb \