[iwm] Implement apmg_wake_up_wa workaround properly for 7000 family.

• Add iwm_pcie_set_cmd_in_flight() and iwm_pcie_clear_cmd_in_flight() helper methods.

• Use ring->queued tracking in the command queue to set/clear the cmd_hold_nic_awake bit at the right points.

Taken-From: Linux iwlwifi

Obtained from: DragonflyBSD commit ce43f57f5308b579ea21e8a5a29969114ba2247d