staging: octeon: fix line over 80 characters

ethernet-rx.c:

fix WARNING: line over 80 characters

The code was restructured a bit, a helper function
was added to cvm_oct_poll.

Signed-off-by: John Smith <catalinnow@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>