wil6210: NAPI completion refactor

It is expected that driver completes NAPI when less than
full budget is consumed.

Fulfill this requirement.

Change-Id: Ifb5a2a2bb06c69c7adcaa66c28304f0f026b349f
Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Git-commit: 7308a20e7579f91e103398366d9bb382653cbb89
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-testing.git


Signed-off-by: Hamad Kadmany <hkadmany@codeaurora.org>