staging: silicom: remove redundant pci_get_drvdata() call

The pci_get_drvdata() and checking NULL for dev are
called twice in while loop in is_bypass_dev().

Signed-off-by: Daeseok Youn <daeseok.youn@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>