urtwn(4): add WME support

[avos]

Rebase.

[adrian]

This is a really big diff and looks like it includes more than "add wme support". What's going on?

[avos]

In D4020#92682, @adrian wrote:

This is a really big diff and looks like it includes more than "add wme support". What's going on?

[Differential] [Updated, 82 lines]

not bigger than D3700

Changes:

• Add wme_to_queue structure for 'access category' <-> 'corresponding register / pipe' mapping;
• Add IEEE80211_C_WME bit;

urtwn_tx_data():

• restore hasqos variable;
• set traffic id;

urtwn_tx_start():

• eliminate urtwn_pipes array (queue id can be fetched via wme2queue[ac].qid structure member);

urtwn_wme_update():

• calculate aifs & set R92C_EDCA_XX_PARAM (AIFS, ECWMIN, ECWMAX, TXOP);
• write ACM parameters into R92C_ACMHWCTRL;

if_urtwnreg.h:

• add R92C_ACMHWCTRL bits;

if_urtwnvar.h:

• remove unused ac2idx array;

[adrian]

ok, as long as kevin is okay with it, go for it!

just make sure you mention which chipsets it's been tested on!