qcacmn: Allow NAN LOG messages upto a size of 400 bytes

Currently, host allows NAN log messages from firmware upto a max
size of 200 bytes. But firmware may need to send bigger messages
than this in case of stats events as tx/rx stats message length
can go upto 350 bytes.
So, allow NAN messages upto 400 bytes to avoid splitting
the stats messages.

Change-Id: Ibb03944da81ed8d378dadbf4750013e0fe941e57
CRs-Fixed: 3049258