bnxt_en: Fix offline ethtool selftest with RDMA enabled

For offline (destructive) self tests, we need to stop the RDMA driver
first.  Otherwise, the RDMA driver will run into unrecoverable errors
when destructive firmware tests are being performed.

The irq_re_init parameter used in the half close and half open
sequence when preparing the NIC for offline tests should be set to
true because the RDMA driver will free all IRQs before the offline
tests begin.

Fixes: 55fd0cf3

 ("bnxt_en: Add external loopback test to ethtool selftest.")
Reviewed-by: Edwin Peer <edwin.peer@broadcom.com>
Reviewed-by: Ben Li <ben.li@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>