wil6210: add advanced interrupt moderation

Add advanced interrupt moderation support available since "Sparrow B0".
Legacy interrupt moderation used only one counter to moderate tx, rx,
and misc interrupts.
Advanced interrupt moderation bypasses misc, and handles separately tx
and rx interrupts. In addition it has two timers for each interrupt type.
Max burst duration timer which defines how long to postpone interrupt after
first event (receive event for rx and tx complete event for tx), and
interframe timeout which defines how to determine the end of the burst and
issue interrupt even if the first timer still pending.
Capabilities flags in wil_priv is set on initialization according to
HW. The rest of the code checks for advanced interrupt capability bit
in capabilities flags field.
Debugfs is split accordingly: "legacy" interrupt moderation remains
unchanged, new debugs files added for advanced interrupt moderation
support.
Module params are aligned to support advanced interrupt moderation
(tx & rx). When not available (for legacy interrupt moderation) will
use only rx configuration; Tx configuration will be ignored in this
case.

Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>