ALSA: usb-audio: Add quirk flag for Edifier MF200

The UAC mixer of Edifier MF200 works fine except that its volume GET_CUR
method is somehow stubbed and returns a constant value. Since commit
86aa1ea ("ALSA: usb-audio: Do not expose sticky mixers"), the
sticky check considers the mixer to be sticky and unnecessarily disables
the mixer.

Add a quirk table entry matching VID/PID=0x2d99/0xa024 and applying
the MIXER_SKIP_GET_CUR_VOL quirk flag, so that the mixer is usable
again.

Quirky device sample:

  usb 1-3.2: new full-speed USB device number 7 using xhci_hcd
  usb 1-3.2: New USB device found, idVendor=2d99, idProduct=a024, bcdDevice= 0.00
  usb 1-3.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
  usb 1-3.2: Product: EDIFIER MF200
  usb 1-3.2: Manufacturer: EDIFIER
  usb 1-3.2: SerialNumber: EDI00000X06
  input: EDIFIER EDIFIER MF200 Consumer Control as /devices/pci0000:00/0000:00:02.1/0000:05:00.0/0000:06:0c.0/0000:0e:00.0/usb1/1-3/1-3.2/1-3.2:1.0/0003:2D99:A024.0003/input/input8
  input: EDIFIER EDIFIER MF200 Mouse as /devices/pci0000:00/0000:00:02.1/0000:05:00.0/0000:06:0c.0/0000:0e:00.0/usb1/1-3/1-3.2/1-3.2:1.0/0003:2D99:A024.0003/input/input9
  input: EDIFIER EDIFIER MF200 Keyboard as /devices/pci0000:00/0000:00:02.1/0000:05:00.0/0000:06:0c.0/0000:0e:00.0/usb1/1-3/1-3.2/1-3.2:1.0/0003:2D99:A024.0003/input/input10
  input: EDIFIER EDIFIER MF200 as /devices/pci0000:00/0000:00:02.1/0000:05:00.0/0000:06:0c.0/0000:0e:00.0/usb1/1-3/1-3.2/1-3.2:1.0/0003:2D99:A024.0003/input/input11
  input: EDIFIER EDIFIER MF200 as /devices/pci0000:00/0000:00:02.1/0000:05:00.0/0000:06:0c.0/0000:0e:00.0/usb1/1-3/1-3.2/1-3.2:1.0/0003:2D99:A024.0003/input/input12
  hid-generic 0003:2D99:A024.0003: input,hiddev1,hidraw2: USB HID v1.10 Mouse [EDIFIER EDIFIER MF200] on usb-0000:0e:00.0-3.2/input0
  usb 1-3.2: 9:1: sticky mixer values (-32768/-32513/1 => -32702), disabling

Reported-by: Steve Smith <tarkasteve@gmail.com>
Closes: https://lore.kernel.org/r/CAHLWS5FJCx66GQ-O10pu+nEudEo_QgQAM9vt76T7vT0zGPPC1g@mail.gmail.com
Tested-by: Steve Smith <tarkasteve@gmail.com>
Signed-off-by: Rong Zhang <i@rong.moe>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20260531-uac-quirk-get-cur-vol-v4-3-ede643dca151@rong.moe

Author: Rongronggg9

sound/usb/quirks.c

@@ -2477,6 +2477,8 @@ static const struct usb_audio_quirk_flags_table quirk_flags_table[] = {
 		   QUIRK_FLAG_CTL_MSG_DELAY_1M),
 	DEVICE_FLG(0x2d99, 0x0026, /* HECATE G2 GAMING HEADSET */
 		   QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE),
+	DEVICE_FLG(0x2d99, 0xa024, /* Edifier MF200 */
+		   QUIRK_FLAG_MIXER_GET_CUR_BROKEN),
 	DEVICE_FLG(0x2fc6, 0xf06b, /* MOONDROP Moonriver2 Ti */
 		   QUIRK_FLAG_CTL_MSG_DELAY),
 	DEVICE_FLG(0x2fc6, 0xf0b7, /* iBasso DC07 Pro */