Bugfixes & MTD create command

Fix some bugs in the cgpt implementation of the flash I/O functions & load
logic, it was validating too much at load time.

Implement the create command for MTD

TEST=MTD version of run_cgpt_tests.sh passes

Change-Id: I2f52637d82962f4d805aa827c5c37685f10e76ea
Reviewed-on: https://gerrit.chromium.org/gerrit/47172
Tested-by: Albert Chaulk <achaulk@chromium.org>
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Commit-Queue: Albert Chaulk <achaulk@chromium.org>
5 files changed