* Merge in changes from FreeBSD with some modification

*	Merge in changes from FreeBSD with some modification
	by drhodus.

date: 2003/12/02 07:57:20;  author: ps;  state: Exp;
After extensive QA cycles at 3ware, bring the driver in-line with all the
issues which they found and asked to be changed so 3ware can offcially
support the driver.

Summary of the most significant changes:

- TWE_OVERRIDE is no longer supported
- If twe_getparam failed, bogus data would be returned to the caller
- Cache the device unit in the twe_drive structure to aid debugging
- Add the 3ware driver version.
- Proper return error codes for many functions.
- Track the minimum queue length statistics
- 4.x compat: use the cached unit number from the twe_drive structure
  instead of the the cached si_drv2.  3ware found that after many loads
   and unloads that si_drv2 became corrupted.  This did not happen in
   -current.