cnss2: Download qdss cfg file at end of fw mem ready handler

Download qdss cfg file at end of fw mem ready handler instead
of downloading cfg file after fw init done. Wlan fw expects
qdss mem req/resp from host before mode on request from it.
Wlan fw will wait for qdss memory sync qmi exchange from
host before sending fw init done to it to avoid receiving
qdss memory sync after mode on request.

Change-Id: If4e752c398821a5cdfeb1b5aeaf735f1973b5635
Signed-off-by: Sandeep Singh <sandsing@codeaurora.org>