CHROMIUM: ath10k: fully enforce the firmware queue limit.

Check firmware queue's airtime limit when releasing packets to
firmware from the path called by ath10k_htt_txrx_compl_task().

BUG=b:131197056
TEST=wireless stress and latency under load test.

Change-Id: Icd20b063216f415afa595c0d63ab5bfdd6684db7
Signed-off-by: Kan Yan <kyan@google.com>
Reviewed-on: https://chromium-review.googlesource.com/1726469


Tested-by: Kan Yan <kyan@chromium.org>
Commit-Ready: Kan Yan <kyan@chromium.org>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Julan Hsu <julanhsu@google.com>
Reviewed-by: Kan Yan <kyan@chromium.org>