Build: rename FIP_ADD_IMG to TOOL_ADD_IMG

Now FIP_ADD_IMG takes care of both fiptool and cert_create
symmetrically.  Rename it so that it matches the behavior.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/Makefile b/Makefile
index 0fe9b08..a9618f5 100644
--- a/Makefile
+++ b/Makefile
@@ -598,38 +598,38 @@
 FIP_BL2_ARGS := tb-fw
 endif
 
-$(if ${BL2}, $(eval $(call FIP_ADD_IMG,BL2,--${FIP_BL2_ARGS})),\
+$(if ${BL2}, $(eval $(call TOOL_ADD_IMG,BL2,--${FIP_BL2_ARGS})),\
 	$(eval $(call MAKE_BL,2,${FIP_BL2_ARGS})))
 endif
 
 ifeq (${NEED_SCP_BL2},yes)
-$(eval $(call FIP_ADD_IMG,SCP_BL2,--scp-fw))
+$(eval $(call TOOL_ADD_IMG,SCP_BL2,--scp-fw))
 endif
 
 ifeq (${NEED_BL31},yes)
 BL31_SOURCES += ${SPD_SOURCES}
-$(if ${BL31}, $(eval $(call FIP_ADD_IMG,BL31,--soc-fw)),\
+$(if ${BL31}, $(eval $(call TOOL_ADD_IMG,BL31,--soc-fw)),\
 	$(eval $(call MAKE_BL,31,soc-fw)))
 endif
 
 # If a BL32 image is needed but neither BL32 nor BL32_SOURCES is defined, the
-# build system will call FIP_ADD_IMG to print a warning message and abort the
+# build system will call TOOL_ADD_IMG to print a warning message and abort the
 # process. Note that the dependency on BL32 applies to the FIP only.
 ifeq (${NEED_BL32},yes)
 
 BUILD_BL32 := $(if $(BL32),,$(if $(BL32_SOURCES),1))
 
 $(if ${BUILD_BL32}, $(eval $(call MAKE_BL,32,tos-fw)),\
-	$(eval $(call FIP_ADD_IMG,BL32,--tos-fw)))
+	$(eval $(call TOOL_ADD_IMG,BL32,--tos-fw)))
 endif
 
 # Add the BL33 image if required by the platform
 ifeq (${NEED_BL33},yes)
-$(eval $(call FIP_ADD_IMG,BL33,--nt-fw))
+$(eval $(call TOOL_ADD_IMG,BL33,--nt-fw))
 endif
 
 ifeq (${NEED_BL2U},yes)
-$(if ${BL2U}, $(eval $(call FIP_ADD_IMG,BL2U,--ap-fwu-cfg,FWU_)),\
+$(if ${BL2U}, $(eval $(call TOOL_ADD_IMG,BL2U,--ap-fwu-cfg,FWU_)),\
 	$(eval $(call MAKE_BL,2u,ap-fwu-cfg,FWU_)))
 endif