trace: Correct the relocation handover with buffer overflow

trace: Correct the relocation handover with buffer overflow

When the early trace buffer overflows it leaves a gap in the trace buffer
between where the actual data finished and where it would have finished if
there were enough buffer space. This results in corrupted output.

Adjust the logic to resolve this and add a message when the buffer
overflows.

Signed-off-by: Simon Glass <sjg@chromium.org>