IB/srp: Remove a superfluous check from srp_free_req_data()

The function srp_free_req_data() does not use ch->target.
Hence remove the ch->target != NULL check.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>