hikey: enable CFG_DT

Patches exist on a-t-f to make it provide a pseudo
device ID via DTB when it starts OP-TEE.

If you are using the patched a-t-f, enable DTB support
for hikey to have the pseudo device ID used auto-
matically in OP-TEE.

Signed-off-by: Andy Green <andy@warmcat.com>

core/arch/arm/plat-hikey/conf.mk

@@ -24,6 +24,8 @@ CFG_NUM_THREADS ?= 8
 CFG_CRYPTO_WITH_CE ?= y
 CFG_WITH_STACK_CANARIES ?= y
 
+$(call force,CFG_DT,y)
+
 CFG_PL061 ?= y
 CFG_PL022 ?= y
 CFG_SPI ?= y