bus: remove useless plug parameter

bus: remove useless plug parameter

The prior scan should link the relevant rte_devargs to the newly
allocated rte_device. As such, it is useless to pass device arguments to
the plug callback. Those arguments are available within the devargs
field of the rte_device structure.

Fixes: 7c8810f43f6e ("bus: introduce device plug/unplug")
Fixes: 00e62aae69c0 ("bus/pci: implement plug/unplug operations")
Fixes: a3ee360f4440 ("eal: add hotplug add/remove device")

Signed-off-by: Gaetan Rivet <gaetan.rivet@6wind.com>