There is a possible race condition that target_start can be
called during load unload leading to htt_srng_setup being
called before monitor srngs are initialized. This check will
prevent the srng_setup_call from soc_start. The rings will
subsequently be initialized when monitor modle is loaded.
Change-Id: Ie697b45425e38e6d709b7466bb495a20bef4f820
CRs-Fixed: 3125255
ec3bfd9dc9