update/blobs: don't needlessly re-build uefitool

during the switch to src/ for all downloads, i
overlooked that the path check was hardcoded.

now the check for this binary is corrected.

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

script/update/blobs/download

@@ -46,7 +46,7 @@ build_dependencies()
 		[ -d "${d}" ] && continue
 		x_ ./update project repo "${d}"
 	done
-	[ -f uefitool/uefiextract ] || \
+	[ -f "${uefiextract}" ] || \
 		x_ ./update project build -b uefitool
 	[ -f "${cbdir}/util/kbc1126/kbc1126_ec_dump" ] || \
 		x_ make -C "${cbdir}/util/kbc1126"