MFC r321510:

[iwm] Add iwm_mvm_send_lq_cmd() from Linux iwlwifi to if_iwm_util.c.

MFC r318230:

[iwm] Fix iwm_mvm_send_cmd_pdu(_status) declarations. Make id a uint32_t.

* This fixes cases where the group id of wide commands got lost, e.g. this
happened to the IWM_SCAN_ABORT_UMAC command.

MFC r318222:

[iwm] Factor out firmware station handling into if_iwm_sta.c.

* This adds iwm_mvm_rm_sta(), which will be used to tear down firmware
state for better/cleaner iwm_newstate() handling.

* Makes iwm_enable_txq() and iwm_mvm_flush_tx_path() non-static, add
the declarations to if_iwm_util.h for now.

MFC r318012:

[iwm] Allow listening on both chains/atennas to get diversity.

This might improve throughput slightly when far from the accesspoint,
apparently by allowing the firmware to listen on either of the two
antennas (if there are two, i.e. on 7260/7265/8260), whichever has
a better reception.

MFC r315926:

[iwm] Add the BSS's basic rates to iwm's LQ command, not all the rates.

Makes the firmware use appropriate Tx rates for ACKs.

MFC r314082:

[iwm] Move iwm_dma_contig_alloc/_free functions to if_iwm_util.c.

MFC r313314:

[iwm] Sync valid_tx_ant and valid_rx_ant mask handling with iwlwifi.

* This fixes the phy_cfg field sent in the iwm_send_phy_cfg_cmd()
command, which wasn't taking into account the valid_rx_ant and
valid_tx_ant masks from nvm_data before.

Tested:

* 7260, STA mode, 2G and 5G

MFC r303322,303326,303327,303345,303413,303416,303418,303557

Update iwm(4) and iwmfw(4) to current in order to stabilize and improve
functionality.

Approved by: re (gjb)