[PATCH 2/4] Fix remove wrong extended prefix

[Denis Kenzior]

Hi Zhenhua,

> ATA, ATH and ATD are belongs to basic command. So removed them.

All of these need to be handled by user callbacks, so effectively they need to 
be treated like extended commands.  Especially with the weird ATD syntax rules 
that 27.007 introduces.

Regards,
-Denis