scsi: aic7xxx: Fix build using bare-metal toolchain

Bare-metal toolchains don't define __linux__, so aic7xxx build with
bare-metal toolchain is broken. This driver codebase used to be partially
shared with FreeBSD, but these days there is no point in keeping the
compatibility around. So let's just drop FreeBSD related code and get rid
of __linux__ checking in order to fix the build using bare-metal
toolchains.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!