setup/fio-setup-basic: fix incorrect raw disk capacity calculation

[findns94]

This commit can fix when /dev is not shown in df command in ubuntu 24.04. When doing fio with raw disk, we should use lsblk to get disk capacity in bytes instead of reading filesystem stats because raw disk will not mount filesystem

Fix for the following error: "storage /dev/disk doesn't mounted" when doing fio with raw disk

[rli9]

thanks for the patch