makechips.sh: Autodetect EM100 utility version

The download URL will always have the latest version, so
assuming a version number when downloading breaks the script.
Instead, extract the version from the downloaded rar ball.

Change-Id: I465596116c0f340584dbf02a4e853c347e59938c
Signed-off-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-on: https://review.coreboot.org/12752
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
1 file changed