drm/xe: Fix memory leak in xe_vm_madvise_ioctl

drm/xe: Fix memory leak in xe_vm_madvise_ioctl

When check_bo_args_are_sane() validation fails, jump to the new
free_vmas cleanup label to properly free the allocated resources.
This ensures proper cleanup in this error path.

Fixes: 293032eec4ba ("drm/xe/bo: Update atomic_access attribute on madvise")
Cc: stable@vger.kernel.org # v6.18+
Reviewed-by: Shuicheng Lin <shuicheng.lin@intel.com>
Signed-off-by: Varun Gupta <varun.gupta@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20260223175145.1532801-1-varun.gupta@intel.com
Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>