drm/xe: improve readability of debugfs engine info output

drm/xe: improve readability of debugfs engine info output

Improve the readability of the info debugfs output by replacing
raw numeric engine masks with human-readable engine and class
names.

Also print per-GT engine capability data in a form that is easier
for a human to interpret directly, and as a side effect simpler
for IGT tests to use when validating engine capabilities.

Reviewed-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Xin Wang <x.wang@intel.com>
Link: https://patch.msgid.link/20260402180552.24121-2-x.wang@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>