util/docker: Update coreboot-sdk dockerfile

- Update the dockerfile which generates the base docker image for the
coreboot builders to include gnat.  This matches the changes made in
the crossgcc/Dockerfile in commit 6b28fff0b (crossgcc/Dockerfile: Add
gnat to build the Ada toolchain).

- Remove the -b from the toolchain build command line.  This doesn't
seem to be needed.

Change-Id: I26d4dca5805f57cab50065cf1c25164b909a0b3d
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/18961
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Philippe Mathieu-Daudé <philippe.mathieu.daude@gmail.com>
Reviewed-by: Nico Huber <nico.h@gmx.de>
1 file changed