power: smb-lib: always assume legacy cable to prevent CC OV

While in DRP the legacy cable detection may fail. Legacy cable
detection is essential to preventing CC OV damage.

Always assume a legacy cable since the legacy cable detection will fail
in some cases. As a side effect, non-legacy HVDCP adapters will stay at
5V if they have a 10k ohm Rp.

To realize this:
- Remove disallowing PD based on the legacy bit being set. That bit set
  or unset is not reliable and it is safe to try PD.
- Remove the workaround which tries to fix legacy cable being set
  incorrectly at boot. That bit set or unset is not reliable.

Change-Id: I37879866592f63906a7c688f51c309b4e2fee48d
Signed-off-by: Nicholas Troast <ntroast@codeaurora.org>
2 files changed