Revert "Staging: dgrp: Refactor the function dgrp_receive() in drrp_net_ops.c"

This reverts commit b73db547.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reported-by: Chen Gang <gang.chen.5i5j@gmail.com>
Cc: Rashika Kheria <rashika.kheria@gmail.com>
Cc: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>