eal: simplify parameters of hotplug functions

eal: simplify parameters of hotplug functions

All information about a device to probe can be grouped
in a common string, which is what we usually call devargs.
An application should not have to parse this string before
calling the EAL probe function.
And the syntax could evolve to be more complex and support
matching multiple devices in one string.
That's why the bus name and device name should be removed from
rte_eal_hotplug_add().
Instead of changing this function, a simpler one is added
and used in the old one, which may be deprecated later.

When removing a device, we already know its rte_device handle
which can be directly passed as parameter of rte_eal_hotplug_remove().
If the rte_device is not known, it can be retrieved with the devargs,
by iterating in the device list (future RTE_DEV_FOREACH()).
Similarly to the probing case, a new function is added
and used in the old one, which may be deprecated later.
The new function is used in failsafe, because the replacement is easy.

Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
Reviewed-by: Andrew Rybchenko <arybchenko@solarflare.com>
Acked-by: Gaetan Rivet <gaetan.rivet@6wind.com>
Reviewed-by: Stephen Hemminger <stephen@networkplumber.org>