Staging: silicom: remove the bpctl_dev_t typdef

Replace the bpctl_dev_t typdef in bpctl_mod.c with struct bpctl_dev
for coding style compliance.

Signed-off-by: Chad Williamson <chad@dahc.us>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>