[TG3]: remove sparse warnings

Removed sparse warnings from tg3 driver.  The new logic seems fine (I
don't immediately see where we are running over values for any of the
variables that need to be saved).

This patch compiles fine and I'm currently using a tg3 with the patched
driver to post this patch as a basic proof of concept.

Signed-off-by: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: David S. Miller <davem@davemloft.net>