HP EliteBook 845 G10 internal microphone not working on Linux (ALC245, SSID 103c:8b72) — needs kernel fixup

Hi,

I'm reporting a bug where the internal microphone does not work on the
HP EliteBook 845 14 inch G10 Notebook PC running Linux kernel 7.0.5-arch1-1.

The microphone works correctly on Windows. On Linux, the internal mic
pin (0x12) is correctly detected by the kernel autoconfig:

  snd_hda_codec_alc269 hdaudioC1D0: ALC245: picked fixup for codec SSID
103c:8b72
  snd_hda_codec_alc269 hdaudioC1D0: inputs:
  snd_hda_codec_alc269 hdaudioC1D0:   Internal Mic=0x12
  snd_hda_codec_alc269 hdaudioC1D0:   Mic=0x19

The internal mic appears in pavucontrol but captures no audio. Both
the "Internal Microphone" and "Microphone" ports in pavucontrol appear
to capture from pin 0x19 (the headphone jack mic) only.

Pin 0x12 details:
  Pincap 0x00000020: IN
  Pin Default 0x90a60130: [Fixed] Mic at Int N/A
  Misc = NO_PRESENCE
  Pin-ctls: 0x20: IN

Node 0x23 (ADC mixer feeding ADC 0x08):
  Connection: 0x19 0x1a 0x1b 0x1d 0x12
  Amp-In vals: [0x00 0x00] [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x80 0x80]

The current fixup for 103c:8b72 is ALC287_FIXUP_CS35L41_I2C_2_HP_GPIO_LED
which only handles the CS35L41 amplifier and LED. No mic routing fixup
is applied.

Machine info:
  Manufacturer: HP
  Product: HP EliteBook 845 14 inch G10 Notebook PC
  Codec: Realtek ALC245 (Vendor Id: 0x10ec0245, Subsystem Id: 0x103c8b72)
  Kernel: 7.0.5-arch1-1
  BIOS: V82 Ver. 01.11.00

Please let me know if any additional information is needed.

Thanks