drm/xe/lrc: Refactor context init into xe_lrc_ctx_init()

drm/xe/lrc: Refactor context init into xe_lrc_ctx_init()

Currently xe_lrc_init() does two things.

1. Allocates LRC bo based on exec queue parameters.
2. Initializes LRC bo with actual context details.

Introduce xe_lrc_ctx_init() and split these two implementations for
better maintainability.

Signed-off-by: Raag Jadav <raag.jadav@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20260302082757.3516577-1-raag.jadav@intel.com