arm: dts: add missing vexpress device trees

Add the device trees for

* vexpress_ca5x2_defconfig
* vexpress_ca9x4_defconfig
* vexpress_ca15_tc2_defconfig

as available in Linux 5.1 rc5.

We are using the vexpress_ca15_tc2_defconfig and vexpress_ca9x4_defconfig
for Travis testing via QEMU.

The UEFI base Embedded Base Boot Requirements Specification (EBBR) requires
that an embedded board either provides a device tree or an ACPI table.

All block devices are meant to be moved to the driver model. On ARM this
requires a device tree.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/arch/arm/dts/Makefile b/arch/arm/dts/Makefile
index 1366ae9..b4dc57e 100644
--- a/arch/arm/dts/Makefile
+++ b/arch/arm/dts/Makefile
@@ -724,6 +724,10 @@
 dtb-$(CONFIG_TARGET_GE_BX50V3) += imx6q-bx50v3.dtb
 dtb-$(CONFIG_TARGET_MX53PPD) += imx53-ppd.dtb
 
+dtb-$(CONFIG_TARGET_VEXPRESS_CA5X2) += vexpress-v2p-ca5s.dtb
+dtb-$(CONFIG_TARGET_VEXPRESS_CA9X4) += vexpress-v2p-ca9.dtb
+dtb-$(CONFIG_TARGET_VEXPRESS_CA15_TC2) += vexpress-v2p-ca15_a7.dtb
+
 targets += $(dtb-y)
 
 # Add any required device tree compiler flags here