scsi: sd: Fix sd_do_mode_sense() buffer length handling

For devices that explicitly asked for MODE SENSE(10) use, make sure that
scsi_mode_sense() is called with a buffer of at least 8 bytes so that the
sense header fits.

Link: https://lore.kernel.org/r/20210820070255.682775-4-damien.lemoal@wdc.com


Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>