fw_config: Return false in `fw_config_probe` in unprovisioned case

fw_config is unprovisioned in the factory for the first boot. This is
the only case where fw_config is left unprovisioned. On first boot in
factory, fw_config gets correctly provisioned by the factory
toolkit. When fw_config is unprovisioned, it is not always possible to
make a guess which device to enable/disable since there can be certain
conflicting devices which can never be enabled at the same time. That
is the reason the original implementation of fw_config library kept
fw_config as 0 when it was unprovisioned.

CB:47956 ("fw_config: Use UNDEFINED_FW_CONFIG to mean unprovisioned")
added support for a special unprovisioned value to allow any callers
to identify this factory boot condition and take any appropriate
action required for this boot (Ideally, this would just involve
configuring any boot devices essential to getting to OS. All other
non-essential devices can be kept disabled until fw_config is properly
provisioned). However, CB:47956 missed handling the
`fw_config_probe()` function and resulted in silent change in behavior.

This change fixes the regression introduced by CB:47956 and returns
`false` in `fw_config_probe()` if fw_config is not provisioned yet.

Change-Id: Ic22cd650d3eb3a6016fa2e2775ea8272405ee23b
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/54750
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>
Reviewed-by: EricR Lai <ericr_lai@compal.corp-partner.google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

0 files changed, 0 insertions, 0 deletions