Coresight: Change to read the trace ID from coresight_path

The source device can directly read the trace ID from the coresight_path
which result in etm_read_alloc_trace_id and etm4_read_alloc_trace_id being
deleted.

Co-developed-by: James Clark <james.clark@linaro.org>
Signed-off-by: James Clark <james.clark@linaro.org>
Signed-off-by: Jie Gan <quic_jiegan@quicinc.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20250303032931.2500935-7-quic_jiegan@quicinc.com