This callback is never called, so remove support.

Link: https://lore.kernel.org/r/1645112566-115804-4-git-send-email-john.garry@huawei.comTested-by: NYihang Li <liyihang6@hisilicon.com>
Tested-by: NDamien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: NJack Wang <jinpu.wang@ionos.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NXiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: NJohn Garry <john.garry@huawei.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>