wlan: Kernel NL ready indication fix

When kernel NL interface is ready,
kernel driver should send indication to PTT app.
To send indication, init flag should be set when NL interface init.
With merging problem, one flag set procedure missed.
Then kernel driver does not send NL ready indication to APP.

Change-Id: I64f17b3de59a5dfa391297f3d838e4dbbd64f159
CRs-fixed: 561215