scsi: sd: sd_read_cpr() requires VPD pages

scsi: sd: sd_read_cpr() requires VPD pages

As such it should be called inside the scsi_device_supports_vpd()
conditional.

Link: https://lore.kernel.org/r/20220302053559.32147-13-martin.petersen@oracle.com
Fixes: e09f2fac4a6e ("scsi: sd: add concurrent positioning ranges support")
Cc: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>