treewide: Use show_notices target for warnings

This updates all warnings currently being printed under the files_added
and build_complete targets to the show_notices target.

Signed-off-by: Martin Roth <gaumless@gmail.com>
Change-Id: Ia14d790dd377f2892f047059b6d24e5b5c5ea823
Reviewed-on: https://review.coreboot.org/c/coreboot/+/79423
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/ec/51nb/npce985la0dx/Makefile.inc

@@ -7,7 +7,7 @@ ifeq ($(CONFIG_EC_51NB_NPCE985LA0DX_FIRMWARE),y)
 	$(CBFSTOOL) $(obj)/coreboot.rom write -r EC -f $(CONFIG_EC_51NB_NPCE985LA0DX_FW) --fill-upward
 endif
 
-build_complete::
+show_notices::
 ifeq ($(CONFIG_EC_51NB_NPCE985LA0DX_FIRMWARE),)
 	printf "\n** WARNING **\n"
 	printf "You haven't added the firmware blobs for 51NB EC.\n"

src/ec/hp/kbc1126/Makefile.inc

@@ -17,7 +17,7 @@ ecfw2.bin-position := $(CONFIG_KBC1126_FW2_OFFSET)
 ecfw2.bin-type := raw
 endif
 
-build_complete::
+show_notices::
 ifeq ($(CONFIG_KBC1126_FIRMWARE),)
 	printf "\n** WARNING **\n"
 	printf "You haven't added the firmware blobs for KBC1126 EC.\n"

src/ec/starlabs/merlin/Makefile.inc

@@ -15,7 +15,7 @@ ifeq ($(CONFIG_EC_STARLABS_ADD_ITE_BIN),y)
 add_ite_fw: $(obj)/coreboot.pre
 	$(CBFSTOOL) $(obj)/coreboot.pre write -r EC -f $(CONFIG_EC_STARLABS_ITE_BIN_PATH) -u
 else
-files_added:: warn_no_ite_fw
+show_notices:: warn_no_ite_fw
 
 PHONY+=warn_no_ite_fw
 warn_no_ite_fw: