app/testpmd: allow detaching a port not closed

app/testpmd: allow detaching a port not closed

The testpmd application aim is for testing;
so order of operations should not be enforced.

There was a test to forbid detaching before closing a port.
However, it may interesting to test what happens in such case.
It is possible for a PMD to automatically close the port when detaching.

in order to avoid a crash, it is checked that the port must be stopped
before detaching (as for closing).

Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: Bernard Iremonger <bernard.iremonger@intel.com>