io->sgl is allocated by kzalloc(). The memory is set to zero.
It is unnecessary to call memset again.

Link: https://lore.kernel.org/r/20220318145230.1031-1-wanjiabing@vivo.comSigned-off-by: Wan Jiabing <wanjiabing@vivo.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>