tests/: Add flashrom.c unit tests

BUG=b:157280555
BRANCH=none
TEST=builds

Change-Id: I2d9213f98c6c9639f2417466ba4895117e8d600a
Signed-off-by: Edward O'Callaghan <quasisec@google.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/41646
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
4 files changed