feat(brbe): add brbe under feature detection mechanism

This change adds "FEAT_BRBE" to be part of feature detection mechanism.

Previously feature enablement flags were of boolean type, possessing
either 0 or 1. With the introduction of feature detection procedure
we now support three states for feature enablement build flags(0 to 2).

Accordingly, "ENABLE_BRBE_FOR_NS" flag is now modified from boolean
to numeric type to align with the feature detection.

Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
Change-Id: I1eb52863b4afb10b808e2f0b6584a8a210d0f38c
diff --git a/Makefile b/Makefile
index 3941f86..e0fc0e0 100644
--- a/Makefile
+++ b/Makefile
@@ -1045,7 +1045,6 @@
         COT_DESC_IN_DTB \
         USE_SP804_TIMER \
         PSA_FWU_SUPPORT \
-        ENABLE_BRBE_FOR_NS \
         ENABLE_TRBE_FOR_NS \
         ENABLE_SYS_REG_TRACE_FOR_NS \
         ENABLE_MPMM \
@@ -1062,6 +1061,7 @@
         CTX_INCLUDE_PAUTH_REGS \
         CTX_INCLUDE_MTE_REGS \
         CTX_INCLUDE_NEVE_REGS \
+        ENABLE_BRBE_FOR_NS \
         ENABLE_BTI \
         ENABLE_PAUTH \
         ENABLE_FEAT_AMUv1 \