Enumerate devices based on SATA host/target

[vovan69]

First of all thanks for a nice code! As I can see the devices enumeration works simply like /dev/sda - led 1, /dev/sdb - led 2, etc. This way isn't really correct. In my case the kernel module even assigns usb disk (/dev/sdb) to the second bay HDD led, which is actually empty. IMO, it would be better to assign leds based on SCSI or SATA host enumeration.