feat(trf): enable trace filter control register access from lower NS EL

Introduced a build flag 'ENABLE_TRF_FOR_NS' to enable trace filter
control registers access in NS-EL2, or NS-EL1 (when NS-EL2 is
implemented but unused).

Change-Id: If3f53b8173a5573424b9a405a4bd8c206ffdeb8c
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
diff --git a/Makefile b/Makefile
index 5de0e07..b9b3176 100644
--- a/Makefile
+++ b/Makefile
@@ -966,6 +966,7 @@
         PSA_FWU_SUPPORT \
         ENABLE_TRBE_FOR_NS \
         ENABLE_SYS_REG_TRACE_FOR_NS \
+        ENABLE_TRF_FOR_NS \
 )))
 
 $(eval $(call assert_numerics,\
@@ -1068,6 +1069,7 @@
         PSA_FWU_SUPPORT \
         ENABLE_TRBE_FOR_NS \
         ENABLE_SYS_REG_TRACE_FOR_NS \
+        ENABLE_TRF_FOR_NS \
 )))
 
 ifeq (${SANITIZE_UB},trap)