szedata2: change to physical device type

szedata2: change to physical device type

PMD was of type PMD_VDEV which means that PCI device is not recognised
automatically during EAL initialization, but it has to be created by
EAL option --vdev.
Now, PMD is of type PMD_PDEV which means that PCI device is probed
and recognised during EAL initialization automatically.
Path to szedata2 device file is matched with device and the count
of available RX and TX DMA channels is found out during device
initialization.
Initialization, starting and stopping of queues is changed to better
correspond with Ethernet device API model. Function callbacks
(rx|tx)_queue_(start|stop) are added. Unnecessary items are removed
from ethernet device private data structure.

Signed-off-by: Matej Vido <vido@cesnet.cz>