SILI - Work around hardware LRAM bugs part 2/2.
* Add ATA_F_AUTOSENSE and ATA_F_EXCLUSIVE to deal with accessing the
D2H RFIS.
ATA_F_AUTOSENSE tells sili.c that the caller wants to access the rfis.
The sili core is then responsible for copying the rfis out of the LRAM
and into host-memory.
ATA_F_EXCLUSIVE tells sili.c that the caller wants to be the only
command queued to the chip for that particular command.
* Currently ATA_F_AUTOSENSE implies ATA_F_EXCLUSIVE, but ultimately we will
want to do the auto-sense as a separate step so things like ATAPI farms
can run commands in parallel.