core-image-sato-sdk-ptest: Fix free space issues causing test failures
Some tests such as strace-ptest require more than the current 500MB of free
space. Increase the amount available, staying under the 4GB limit. We have more
flexibility now since we shrank kernel-devsrc and the comments are out of date
due to that.
This should improve the strace-ptest results and the util-linux ones since
those sort after strace and also hit the space issues as strace-ptest didn't
clean up after itself when failing.
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
