net: tg3: fix obsolete check of !err

The err variable is checked for true or false a few lines above.  When
!err is checked again, it always evaluates to true.  Therefore we should
skip this check.

We should also group the adjacent statements together for readability.

Signed-off-by: Jean Sacren <sakiwit@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>