[PATCH] S2io: Errors found during review

Hi,
This is a patch to incorporate comments from earlier 12 patches.
It also fixes a few issues we found during this time.
Following is a list of changes in this patch. Item 1 incorporates
earlier comments. Issues addressed in items 2 to 4 were discovered
recently.

1. wmb() call in s2io_xmit() replaced with mmiowb().
2. The dtx_control register was earlier programmed incorrectly
   for Xframe II adapter.
3. As suggested by hardware team, after a reset, in case of
   Xframe II adapter, we clear certain spurious errors by
   clearing PCI-X ECC status register, "detected parity error"
   bit in PCI_STATUS register and PCI_STATUS bit in txpic_int register.
4. On IBM PPC platforms, we found that in the Rx buffer replenish
   function, two memory writes(one to the the descriptor length and
   another to the ownership) were getting reordered. This was causing
   the adapter to see the ownership transfered to it before the length
   was updated.

   One solution was to add a wmb() but since this would turnout expensive
   on some platforms if called for every descriptor, we set the ownership
   bit and other fields of '2' to 'N' Rx descriptors followed by a wmb()
   and then set the ownership of first descriptor ('1').

   Here the value 'N' is configurable by making it a module loadable
   parameter (rxsync_frequency).
   (NOTE: This parameter is a power of 2).
5. Bumped up the driver version no. to 2.0.2.1

Signed-off-by: Ravinandan Arakali <ravinandan.arakali@neterion.com>
Signed-off-by: Raghavendra Koushik <raghavendra.koushik@neterion.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>