vexpress: Disable building of perf for standard vexpress builds

Perf build is undergoing some experimentation so lets disable it until
it is stable to avoid build breakages.

Change-Id: I35d2f8c0450653a995ed5e43ba470717fce44bf7
Signed-off-by: Jon Medhurst <tixy@linaro.org>
diff --git a/BoardConfig.mk b/BoardConfig.mk
index db0ae02..a069272 100644
--- a/BoardConfig.mk
+++ b/BoardConfig.mk
@@ -33,6 +33,7 @@
 		rtsm_ve-v2p-ca15x1-ca7x1:rtsm/rtsm_ve-ca15x1-ca7x1.dtb \
 		rtsm_ve-v2p-ca15x4-ca7x4:rtsm/rtsm_ve-ca15x4-ca7x4.dtb
 CUSTOM_BOOTLOADER_MAKEFILE := device/linaro/vexpress/bootloader.mk
+INCLUDE_PERF := 0
 else
 TARGET_USE_UBOOT := false
 DEVICE_TREES := rtsm_ve-v2p-ca15x1-ca7x1:rtsm/rtsm_ve-ca15x1-ca7x1.dtb \