wil6210: TX vring optimization

Tx vring needs to be enlarged to get better
performance for traffic over 2Gbps.

Change-Id: Ia78ddf6f5243a8d28c3bfdfc29e0eb512658d0a7
Signed-off-by: Hamad Kadmany <qca_hkadmany@qca.qualcomm.com>
Signed-off-by: Maya Erez <qca_merez@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
Git-commit: ee5dfe0d
Git-repo: https://github.com/kvalo/ath.git


CRs-Fixed: 982882
Signed-off-by: Maya Erez <merez@codeaurora.org>