lbmk scripts: shorter code lines

while seemingly pedantic, this does actually make code
easier to read. mostly just switching to shorthand for
variable names, where no expansions or patterns are used

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

include/option.sh

@@ -52,7 +52,7 @@ scan_config()
 	done << EOF
 	$(eval "awk '${awkstr}' \"${revfile}\"")
 EOF
-	rm -f "${revfile}" || "${_fail}" "scan_config: Cannot remove tmpfile"
+	rm -f "$revfile" || "$_fail" "scan_config: Cannot remove tmpfile"
 }
 
 check_defconfig()