drm/xe: Add sysfs entries for engines under its GT

Add engines sysfs directory under its GT and
create sub directory for all engine class
(note its not per instance) present on GT.

For example,
DUT# cat /sys/class/drm/cardX/device/tileN/gtN/engines/
bcs/ ccs/

V9 :
   - Add missing drmm_add_action_or_reset
V8 :
   - Rebase
V7 :
   - Remove xe_gt.h from .h and include in .c - Matt
V6 :
   - Add kernel doc and arrange file in make file by alphabet - Matt
V5 :
   - replace xe_engine with xe_hw_engine - Matt
V4 :
   - Rebase to resolve conflicts - CI
V3 :
   - Move code in its own file
   - Rename API name
V2 :
   - Correct class mask logic - Himal
   - Remove extra parenthesis

Reviewed-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>