mhuv3: Implement graceful handling for unavailable channel
- Previously, the process would immediately fail if the communication channel wasn't free.
- This change introduces a waiting mechanism (if timer module is available) to prevent SCMI timeouts in Agents when the channel is busy.
- If the timer module is absent, the process will still check for channel availability once before failing.
Signed-off-by: Tintu Thomas tintu.thomas@arm.com Change-Id: Ife21db21330e8f3b69d3ea6efaa94b2966261304