tests: Make libusb conditional dependency for unit tests

Unit tests had an unconditional dependency on libusb and this was
a) strictly speaking not needed, b) blocking one build system effort.
This patch is a temporary solution to unblock one build system effort,
specifically CB:63724. It creates a condition so that libusb is only
included when it is required, not always.

This workaround is based on the fact that at the moment only
2 lifecycle unit tests are using libusb symbols: dediprog and
raiden_debug.

BUG=b:237606255
TEST=the following scenarios run tests successfully

1) dediprog and raiden_debug programmers enabled, libusb.h present
result:
all test run and pass

2) dediprog disabled, libusb.h present
result:
dediprog test skipped, all other tests run and pass

3) dediprog and raiden_debug both disabled,
libusb.h changed to libusbabcd.h
result:
dediprog and raiden_debug tests are skipped,
all other tests run and pass

Change-Id: Iec8a1826951fd6ae586e90fde1a55170e7de41a8
Signed-off-by: Anastasia Klimchuk <aklm@chromium.org>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/65627
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Singer <felixsinger@posteo.net>
Reviewed-by: Thomas Heijligen <src@posteo.de>

0 files changed, 0 insertions, 0 deletions