fix(tests): FVP S-EL0 tests

Recent changes removed the use of uart as test control mechanism for FVP
tests that run both the hypervsior and SPMC. Updating VHE builds to
remove dependence on uart as hftest control mechanism.

Signed-off-by: Raghu Krishnamurthy <raghu.ncstate@gmail.com>
Change-Id: Ie7bf95ecf1cad1ab7a511608e5741a72bb35baf1
diff --git a/BUILD.gn b/BUILD.gn
index 1c1b567..8b1c66b 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -115,7 +115,6 @@
     plat_prng = "//src/arch/aarch64/plat/prng:prng"
     secure_world = "1"
     pl011_base_address = "0x1c090000"
-    hftest_ctrl = "//test/hftest:ctrl_uart"
     smmu_base_address = "0x2b400000"
     smmu_memory_size = "0x100000"
     enable_vhe = "1"