Install iwlwifi and sof firmware pkgs on nfs images

This is required to enable audio and the Intel AX210 wifi module on the
UP Squared 6000 board.

Without these firmware pkgs, drivers will retry several times. Thus,
lots of kernel msgs are printed to the serial console, which makes LAVA
test fail to parse the login prompt. E.g.:

  [   14.595274] iwlwifi 0000:02:00.0: firmware: failed to load iwlwifi-ty-a0-gf-a0-40.ucode (-2)
  Apertis v2022 apertis ttyS0
  apertis [   14.599430] asus-nb-wmi asus-nb-wmi: Detected BFPI, not ASUSWMI, use DSTS
  [   14.599734] asus_wmi: Failed to set throttle thermal policy (retval): 0xffffffff
  [   14.614016] iwlwifi 0000:02:00.0: Direct firmware load for iwlwifi-ty-a0-gf-a0-40.ucode failed with error -2
  login: [   14.625103] asus-nb-wmi asus-nb-wmi: Using throttle_thermal_policy for platform_profile support
  [   14.644462] iwlwifi 0000:02:00.0: firmware: failed to load iwlwifi-ty-a0-gf-a0-39.ucode (-2)

Signed-off-by: Ariel D'Alessandro <ariel.dalessandro@collabora.com>

recipes/apertis-ospack-nfs.yaml

@@ -10,6 +10,7 @@ actions:
     suite: {{ $suite }}
     components:
       - target
+      - non-free
     mirror: {{ $mirror }}
     variant: minbase
     keyring-package: apertis-archive-keyring
@@ -31,6 +32,12 @@ actions:
       - systemd-sysv
       - libnss-myhostname
 
+  - action: apt
+    description: "Firmware packages"
+    packages:
+      - firmware-iwlwifi
+      - firmware-sof-signed
+
   - action: overlay
     source: overlays/nfs