tg3: Remove function errors flagged by checkpatch

This patch removes the following checkpatch errors:

* return is not a function, parentheses are not required
* space prohibited between function name and open parenthesis '('

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Reviewed-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>