rdma: replace deprecated ifconfig in doc
rdma: replace deprecated ifconfig in doc

The ifconfig command has been deprecated for many years.
To encourage new users not to continue using it and learning
iproute2; the ifconfig should not be used in examples.

Signed-off-by: Stephen Hemminger <06fa905d7f2aaced6dc72e9511c71a2a51e8aead@networkplumber.org>
Signed-off-by: Doug Ledford <f35204f44eabfe97bbcdd18aee9e9fffc59f29e1@redhat.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs