drm/i915/gt: Continue creating engine sysfs files even after a failure

drm/i915/gt: Continue creating engine sysfs files even after a failure

The i915 driver generates sysfs entries for each engine of the
GPU in /sys/class/drm/cardX/engines/.

The process is straightforward: we loop over the UABI engines and
for each one, we:

 - Create the object.
 - Create basic files.
 - If the engine supports timeslicing, create timeslice duration files.
 - If the engine supports preemption, create preemption-related files.
 - Create default value files.

Currently, if any of these steps fail, the process stops, and no
further sysfs files are created.

However, it's not necessary to stop the process on failure.
Instead, we can continue creating the remaining sysfs files for
the other engines. Even if some files fail to be created, the
list of engines can still be retrieved by querying i915.

Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240819113140.325235-1-andi.shyti@linux.intel.com