feat(sme): add basic SME tests

This test enters streaming mode and iterates through supported SME
vector lengths to ensure that EL3 has properly enabled SME for use at
lower non-secure ELs. If FA64 is present, it attempts to execute an
illegal instruction.

Signed-off-by: John Powell <john.powell@arm.com>
Change-Id: Ic80a1e5652a88261524778329d3bc99901a799d8
diff --git a/tftf/tests/tests-cpu-extensions.mk b/tftf/tests/tests-cpu-extensions.mk
index 5ceb340..6563b2a 100644
--- a/tftf/tests/tests-cpu-extensions.mk
+++ b/tftf/tests/tests-cpu-extensions.mk
@@ -18,4 +18,5 @@
 	runtime_services/arm_arch_svc/smccc_arch_soc_id.c		\
 	runtime_services/arm_arch_svc/smccc_arch_workaround_1.c		\
 	runtime_services/arm_arch_svc/smccc_arch_workaround_2.c		\
+	extensions/sme/test_sme.c					\
 )