drm/xe: Covert return of -EBUSY to -ENOMEM in VM bind IOCTL

drm/xe: Covert return of -EBUSY to -ENOMEM in VM bind IOCTL

xe_vma_userptr_pin_pages can return -EBUSY but -EBUSY has special
meaning in VM bind IOCTLs that user fence is pending that is attached to
the VMA. Convert -EBUSY to -ENOMEM in this case as -EBUSY in practice
means we are low or out of memory.

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
Link: https://patch.msgid.link/20251122012502.382587-2-matthew.brost@intel.com