bl2-el3: Don't include BL2 in fip for BL2 at EL3

It is better to not include BL2 in FIP when using `BL2 at EL3` as
platforms using this config would not have the capability to parse the
FIP format in Boot ROM and BL2 needs to be loaded independently. This
patch does the required changes for the same.

Change-Id: Iad285c247b3440e2d827fef97c3dd81f5c09cabc
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>
diff --git a/Makefile b/Makefile
index b97c048..1cd6b62 100644
--- a/Makefile
+++ b/Makefile
@@ -586,8 +586,12 @@
 endif
 
 ifeq (${NEED_BL2},yes)
-$(if ${BL2}, $(eval $(call MAKE_TOOL_ARGS,2,${BL2},tb-fw)),\
-	$(eval $(call MAKE_BL,2,tb-fw)))
+ifeq (${BL2_AT_EL3}, 0)
+FIP_BL2_ARGS := tb-fw
+endif
+
+$(if ${BL2}, $(eval $(call MAKE_TOOL_ARGS,2,${BL2},${FIP_BL2_ARGS})),\
+	$(eval $(call MAKE_BL,2,${FIP_BL2_ARGS})))
 endif
 
 ifeq (${NEED_SCP_BL2},yes)