wlan: Fix roaming delay and roaming count in TSM report

Even though there exists a interface between firmware and driver
firmware does not fill roaming delay and count information.
In the original CCX code, these information are updated in
host driver.

Roaming Count:
Roaming count is incremented whenever ASSOC_RSP is received and
the same variable is used to update the TSM Stats before sending
it to supplicant.

Roaming Delay:
Right after association, CCX enabled STA computes roaming delay
as a part of sending Adjacent AP Report. Fix is added to update
roaming delay global variable here.

Change-Id: I80cef3c96bc123f7e933fce87fc015c3a2201d1c
CRs-Fixed: 567792