Currently there is no synchronization for flush log completion
between fw and userspace. When host driver receives command to
flush logs, it sends the command to fw and releases the control
of the userspace thread, it does not wait for the flush log
completion event from the fw and because of which user space
does not know when the host and fw completes the log flush.
To address above issue add a logic to wait for fw event of
flush log completion before host returns control to userspace.
Change-Id: I04fa0aead146d2b7b8627e4101c6dcd99d3947e9
CRs-Fixed: 2983387
fdac28ef95