net/tap: remove minimum packet size in Rx

net/tap: remove minimum packet size in Rx

With support for segmented packets, it is now possible to easily receive
packets of many sizes, given an adequate number of descriptors.

Remove limitation on the minimum size of mbuf: on reception, if a packet
won't fit in the queue's mbufs, it will be detected in the packet info
and the packet will be discarded.

Fixes: 0781f5762cfe ("net/tap: support segmented mbufs")
Signed-off-by: Pascal Mazon <pascal.mazon@6wind.com>
Acked-by: Keith Wiles <keith.wiles@intel.com>