vexpress: IKS: rename dtb as it is in public build

Change-Id: I26343b53068e82be13c394f56e0bae645baff13a
Signed-off-by: Vishal Bhoj <vishal.bhoj@linaro.org>
diff --git a/BoardConfig.mk b/BoardConfig.mk
index cb603a7..9da53bf 100644
--- a/BoardConfig.mk
+++ b/BoardConfig.mk
@@ -45,7 +45,7 @@
 KERNEL_CONFIG := vexpress_bL_defconfig
 TARGET_USE_UBOOT := true
 UBOOT_CONFIG := vexpress_ca5x2
-DEVICE_TREES := vexpress-v2p-ca15-tc2:vexpress-v2p-ca15-tc2.dtb
+DEVICE_TREES := vexpress-v2p-ca15-tc2:v2p-ca15-tc2.dtb
 endif
 endif
 TARGET_USE_XLOADER := false