drm/xe/trace: Print device_id in xe_trace events

In multi-gpu environments it is important to know the device
gt events belongs to. The tracing information includes the device_id
to indicate the device the event is associated with.

v2: Use variable sized variant to display dev name(Gustavo)
v3: Pass single argument to __assign_str to fix kunit error
v4: Remove unused sting_helper library include

Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240607182943.3572524-6-radhakrishna.sripada@intel.com