Revert "skge: fix ram buffer size calculation"

This reverts commit 7fb7ac24.

Heikki Orsila reports that it causes a regression:

  "Doing

	nc host port < /dev/zero

   on a sending machine (not skge) to an skge machine that is receiving:

	nc -l -p port >/dev/null

   with ~60 MiB/s speed, causes the interface go malfunct. A slow
   transfer doesn't cause a problem."

See

	http://bugzilla.kernel.org/show_bug.cgi?id=9321



for some more information.

There is a workaround (also reported by Heikki):

  "After some fiddling, I noticed that not changing the register write
   order on patch:

   +       skge_write32(hw, RB_ADDR(q, RB_END), end);
           skge_write32(hw, RB_ADDR(q, RB_WP), start);
           skge_write32(hw, RB_ADDR(q, RB_RP), start);
   -       skge_write32(hw, RB_ADDR(q, RB_END), end);

   fixes the visible effect..  Possibly not the root cause of the
   problem, but changing the order back fixes networking here."

but that has yet to be ack'ed or tested more widely, so the whole
problem-causing commit gets reverted until this is resolved properly.

Bisected-and-requested-by: Heikki Orsila <shdl@zakalwe.fi>
Cc: Stephen Hemminger <shemminger@linux-foundation.org>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>