MFC r364341

netmap: fix parsing of legacy nmr->nr_ringid

Code was checking for NETMAP_{SW,HW}_RING in req->nr_ringid which
had already been masked by NETMAP_RING_MASK. Therefore, the comparisons
always failed and set NR_REG_ALL_NIC. Check against the original nmr
structure.

Submitted by: bpoole@packetforensics.com
Reported by: bpoole@packetforensics.com
Reviewed by: giuseppe.lettieri@unipi.it
Approved by: vmaffione