wil6210: increase the frequency of status ring hw tail update

The driver updates Tx status ring HW tail only after it finishes
processing the whole status ring, while the HW is still transmitting
from other transmit rings. This can cause back-pressure on HW if
no status entries are available.

Update HW tail of Tx status ring without waiting for the end of the
processing to help feeding back the HW with status entries and to allow
additional packet transmission.

Change-Id: I938958d1335393f0471b8d18ffc0c7eb2fadfbcd
Signed-off-by: Ahmad Masri <amasri@codeaurora.org>
Signed-off-by: Maya Erez <merez@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Git-commit: 96b77bb044706317d4955129e3ce2580ffb97b82
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/kvalo/ath.git


Signed-off-by: Maya Erez <merez@codeaurora.org>