silicom: remaining checkpatch issues in bypass.c

In this patch we fix some "logical" errors in bypass.c of the silicom bypass
driver (in staging).

Checkpatch complains about the following errors:
 - unnecessary forward declarations in a source file
 - assignment in if condition

In addition to that the __init and __exit macros were missing at the init and
cleanup function.

There are still two warnings left for this file related to too many leadingtabs
at nested blocks. I did not touch this issue becasue the code needs really some
refactoring. And since i do not have the appropriate hardware to test the code,
i do not change the functionality in any way.

Signed-off-by: Michael Hoefler <michael.hoefler@studium.uni-erlangen.de>
Signed-off-by: Christoph Kohl <christoph.kohl@t-online.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>