Instead of having a Travis CI system that constantly timesout let's do
two things:
1. Adjust the Travis CI setup to be as fast as possible. By removing as
many commands as we can, avoiding installing too many dependencies and
doing a shallow git clone we can save time.
2. Use timeout to test each major RISC-V machine for 55 minutes. If we
run until we hit the timeout we count the test as a pass. This should
allow use to rely on the tests passing before merging commits while
also testing all three boards.
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
