drm/xe: Add reg read/write trace

drm/xe: Add reg read/write trace

This will help debug register read/writes and provides
a way to trace all the mmio transactions.

v2: Fix kunit error
v3: Print devid to help in multi-gpu setup
v3: rebase and use variable sized variant to display
    dev name(Gustavo)
v4: Pass single argument to __asign_str to fix kunit error
v5: Remove unrelated include xe_tile.h and remove cast in trace

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/20240607182943.3572524-7-radhakrishna.sripada@intel.com