rom.sh: remove redundant check

if_build / empty mode are a given here, since this
is a premake function which only executes if
the mode string is empty and/or if_build is empty

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

include/fw/rom.sh

@@ -64,7 +64,7 @@ corebootpremake()
 	printf "%s\n" "${version%%-*}" > "$srcdir/.coreboot-version" || \
 	    err "!mk $srcdir .coreboot-version" "corebootpremake" "$@"
 
-	[ -z "$mode" ] && [ "$target" != "$tree" ] && \
+	[ "$target" != "$tree" ] && \
 		x_ "$mk" download "$target"; :
 }