[SCSI] libsas, aic94xx: fix dma mapping cockups with ATA
This one was noticed by Gilbert Wu of Adaptec:
The libata core actually does the DMA mapping for you, so there has to
be an exception in the device drivers that *don't* do dma mapping for
ATA commands. However, since we've already done this, libsas must now
dma map any ATA commands that it wishes to issue ... and yes, this is a
horrible mess.
Additionally, the test in aic94xx for ATA protocols isn't quite right.
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>