samples/bpf: Remove the xdp_rxq_info utility

samples/bpf: Remove the xdp_rxq_info utility

The functionality of this utility has been incorporated into the xdp-bench
utility in xdp-tools, by way of the --rxq-stats argument to the 'drop',
'pass' and 'tx' commands of xdp-bench.

Some examples of how to convert xdp_rxq_info invocations into equivalent
xdp-bench commands:

xdp_rxq_info -d eth0
  --> xdp-bench pass --rxq-stats eth0

xdp_rxq_info -d eth0 -a XDP_DROP -m
  --> xdp-bench drop --rxq-stats -p swap-macs eth0

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/20230824102255.1561885-4-toke@redhat.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>