fix(build): add forgotten BL_LDFLAGS to lto command line

as a result of missing BL_LDFLAGS '-Wl,--sort-section=alignment' was
missing in link arguments for bl31.

Signed-off-by: Andrey Skvortsov <andrej.skvortzov@gmail.com>
Change-Id: I78878e49da21fdc565abb3072e4abaf9face49f4
diff --git a/make_helpers/build_macros.mk b/make_helpers/build_macros.mk
index 71cf18b..08a6046 100644
--- a/make_helpers/build_macros.mk
+++ b/make_helpers/build_macros.mk
@@ -573,7 +573,7 @@
 		$(LDPATHS) $(LIBWRAPPER) $(LDLIBS) $(BL_LIBS) \
 		$(BUILD_DIR)/build_message.o $(OBJS)
 else ifneq ($(findstring gcc,$(notdir $(LD))),)
-	$$(Q)$$(LD) -o $$@ $$(TF_LDFLAGS) $$(LDFLAGS) -Wl,-Map=$(MAPFILE) \
+	$$(Q)$$(LD) -o $$@ $$(TF_LDFLAGS) $$(LDFLAGS) $(BL_LDFLAGS) -Wl,-Map=$(MAPFILE) \
 		$(addprefix -Wl$(comma)--script$(comma),$(LINKER_SCRIPTS)) -Wl,--script,$(DEFAULT_LINKER_SCRIPT) \
 		$(BUILD_DIR)/build_message.o \
 		$(OBJS) $(LDPATHS) $(LIBWRAPPER) $(LDLIBS) $(BL_LIBS)