Make the RDMA test return XFAIL rather than skip when RXE is not
available, since the RDMA datapath is not run in netdev CI.
Change the three RDMA-prerequisite checks in check_rdma_conf() and
check_rdma_conf_enabled() to exit with KSFT_XFAIL (2) and tag their
messages [XFAIL] instead of [SKIP].
Signed-off-by: Allison Henderson <achender@kernel.org>
Link: https://patch.msgid.link/20260602050657.26389-5-achender@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>