type-c-service/tps6699x: Fix EPR capable flag not being set

[RobertZ2011]

This flag was not being set properly.

[Copilot]

Pull request overview

This PR fixes PortStatus.epr reporting for the TPS6699x Type-C/PD controller integration by deriving the flag from the received Source Capabilities (Fixed Supply PDO) rather than leaving it unset. While doing so, it also switches dual_power and unconstrained_power extraction to use the decoded Fixed Supply PDO fields directly. A small documentation tweak updates the PortStatus comment to reflect that epr represents capability (not “mode active”).

Changes:

• Decode the first received source PDO as a Fixed Supply PDO and use it to populate dual_power, unconstrained_power, and epr in sink explicit-contract status.
• Add PortStatus.epr assignment based on epr_capable.
• Update the PortStatus field doc comment to “EPR capable”.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
type-c-service/src/driver/tps6699x.rs	Sets PortStatus.epr (and related partner-power flags) from the decoded Fixed Supply Source PDO when acting as a sink with an explicit contract.
embedded-service/src/type_c/controller.rs	Updates the documentation for PortStatus.epr to reflect capability semantics.

[RobertZ2011]

Forgot to do this in a separate branch, moved to #941.