silicom: fix coding style issues in bypass.c

This patch improves bypass.c (in staging) in terms of coding style. This
includes different issues some of them mentioned by checkpatch:

 - a c++ one line comment
 - parenthesis at return statementes
 - multiple definitions in one line
 - missing braces according to the style guide

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>