drm/xe/uapi: Correct sync type definition in comments

drm/xe/uapi: Correct sync type definition in comments

Commit 37d078e51b4c ("drm/xe/uapi: Split xe_sync types from flags") renamed some DRM_XE_SYNC_*
defines but later commits kept using the old names. Correct them with the new definition.

v2: correct fixes tag and update commit message to explain why (Lucas)

Fixes: 9329f0667215 ("drm/xe/uapi: Use LR abbrev for long-running vms")
Fixes: 4b437893a826 ("drm/xe/uapi: More uAPI documentation additions and cosmetic updates")
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Francois Dugast <francois.dugast@intel.com>
Cc: Zongyao Bai <zongyao.bai@intel.com>
Signed-off-by: Shuicheng Lin <shuicheng.lin@intel.com>
Link: https://lore.kernel.org/r/20250608230133.1250849-1-shuicheng.lin@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>