build/fw/coreboot: don't support no-all all arg

it's buggy. "./build fw coreboot" was made to work,
but it caused lots of unknown issues when mixing other
args

the old way wasn't broken. now, once again, you must
pass the "all" argument. e.g.:

./build fw coreboot all

Also, the confirmation messages at the end are a bit
clearer, when listing which ROM images were compiled.

Signed-off-by: Leah Rowe <leah@libreboot.org>

script/build/fw/coreboot

@@ -45,8 +45,7 @@ main()
 		shift 2
 	done
 
-	[ "${all}" = "y" ] && boards=""
-	[ ! -z ${boards} ] || boards=$(listitems config/coreboot) || \
+	[ "${all}" != "y" ] || boards=$(listitems config/coreboot) || \
 	    err "Cannot generate list of boards for building"
 
 	for x in ${boards}; do
@@ -56,11 +55,12 @@ main()
 		check_target
 		prepare_target
 		[ -d "bin/${board}" ] || continue
-		targets="bin/${board}, ${targets}"
+		targets="* bin/${board}\n${targets}"
 	done
 
 	[ -z ${targets} ] && err "No ROM images were compiled"
-	printf "ROM images available in these directories:\n${targets%, }\n"
+	printf "\nROM images available in these directories:\n"
+	printf "${targets}^^ ROM images available in these directories.\n\n"
 }
 
 check_target()