[SCSI] aacraid: sgraw command support

Received from Mark Salyzyn from Adaptec:

This patch adds support for the new raw io command. This new command
offers much larger io commands, is more friendly to the internal firmware
structure requiring less translation efforts by the firmware and offers
support for targets greater than 2TB (patch to support >2TB will
be sent in the future).

Signed-off-by: Mark Haverkamp <markh@osdl.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>