CHROMIUM: wireless: TX latency per-TID

Rather than maintaining TX latency stats for 4 WMM Access Class (AC)
the stats are now accounted for each of the 16 TID values.

The first 8 TID values encode 802.1D User Priority (UP).  The debugfs
files used to access the stats are named based on mapping the UP to
an extended set of WMM AC names, as follows:
  TID / UP -> File name
  0           AC_BE
  1           AC_BK
  2           AC_BK+
  3           AC_BE+
  4           AC_VI
  5           AC_VI+
  6           AC_VO
  7           AC_VO+
The remaining TID values (8..15) debugfs files used to access the
stats are generically named TID# (i.e. TID8, TID9,...TID15).

This is a port from chromeos-3.18 to chromeos-4.14-gw of
https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/1656951



BUG=b:131335993, b:131196810
TEST=System test using iperf traffic stream with varying TOS mark
     and verified packet stats were accounted into the appropriate
     /sys/kernel/debug/ieee80211/phyX/ath10k/tx_delay_histogram/
     file entry.  TOS 0x00 -> BE, TOS 0x20 -> BK, TOS 0x40 -> BK+,
     TOS 0x60 -> BE+, TOS 0x80 -> VI, TOS 0xA0 -> VI+, TOS 0xC0 -> VO,

Change-Id: I4d91bf00e11758054fa18fa8a4ce36931a3cb69f
Signed-off-by: Danny J. Mitzel <mitzel@google.com>
Reviewed-on: https://chromium-review.googlesource.com/1702942


Tested-by: Danny Mitzel <mitzel@google.com>
Commit-Ready: Danny Mitzel <mitzel@google.com>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Kan Yan <kyan@chromium.org>