#35 Support reporting Device Sleep capabilities.

[David Woodhouse]

This enables the following output for 'hdparm -I' on a device with DevSleep support:

Commands/features:
Enabled Supported:
* Device Sleep (DEVSLP)
Device Sleep:
DEVSLP Exit Timeout (DETO): 20 ms (drive)
Minimum DEVSLP Assertion Time (MDAT): 10 ms (drive)

It also adds text for a few other bits in ID word 0x76.

[David Woodhouse]

Add Device Sleep reporting (including sgio.h change to add ATA_OP_READ_LOG_EXT)

[Mark Lord]

Fantasic! Thanks.
(I don't look here very often, so apologies for the lengthy delay).