IB/srp: Don't schedule reconnect from srp

If there is a problem in the connection, the SCSI mid-layer will
eventually call srp_reset_host(), which will call srp_reconnect(), so
we do not need to schedule a call to srp_reconnect_work() from
srp_completion().

Removing this prevents srp_reset_host() from failing if a reconnect
scheduled from srp_completion() is already in progress, which in turn
was causing crashes as both SCSI midlayer and srp_reconnect() were
cancelling commands.

Signed-off-by: Ishai Rabinovitz <ishai@mellanox.co.il>
Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>