fix(sve): disable ENABLE_SVE_FOR_NS for AARCH32

With patch [1], ENABLE_SVE_FOR_NS is always enable.
Disable it for AARCH32 platforms, as the feature is not supported.
The warning message is replaced with an error, and the second override
is removed.

[1] dc78e62d80e6 ("feat(sme): enable SME functionality")

Change-Id: Ic9c5e2612c9e00bd0d37ca3b59537e39270c9799
Signed-off-by: Yann Gautier <yann.gautier@st.com>
diff --git a/make_helpers/defaults.mk b/make_helpers/defaults.mk
index 72f5e33..551b689 100644
--- a/make_helpers/defaults.mk
+++ b/make_helpers/defaults.mk
@@ -327,6 +327,10 @@
 
 # Enable SVE for non-secure world by default
 ENABLE_SVE_FOR_NS		:= 1
+# SVE is only supported on AArch64 so disable it on AArch32.
+ifeq (${ARCH},aarch32)
+	override ENABLE_SVE_FOR_NS	:= 0
+endif
 ENABLE_SVE_FOR_SWD		:= 0
 
 # SME defaults to disabled