eal: remove experimental tag for probe/remove

eal: remove experimental tag for probe/remove

The functions rte_dev_probe() and rte_dev_remove() are new
in DPDK 18.11 so they got the experimental tag by policy.
However they are too much basic functions for being skipped
by strict applications which do not use experimental functions.

The alternative is to use rte_eal_hotplug_add() and
rte_eal_hotplug_remove(), but their API requires the application
to parse the devargs string in order to provide bus name,
device name and driver arguments.

The new function rte_dev_probe() is really simpler to use and
more flexible by accepting any devargs string.
Let's encourage applications to use it.

The old functions rte_eal_hotplug_* may be deprecated later.

Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: Kevin Traynor <ktraynor@redhat.com>
Tested-by: Kevin Traynor <ktraynor@redhat.com>