usb: gadget: f_uac2: Define specific wTerminalType

Several users have reported that their Win10 does not enumerate UAC2
gadget with the existing wTerminalType set to
UAC_INPUT_TERMINAL_UNDEFINED/UAC_INPUT_TERMINAL_UNDEFINED, e.g.
https://github.com/raspberrypi/linux/issues/4587#issuecomment-926567213.
While the constant is officially defined by the USB terminal types
document, e.g. XMOS firmware for UAC2 (commonly used for Win10) defines
no undefined output terminal type in its usbaudio20.h header.

Therefore wTerminalType of EP-IN is set to
UAC_INPUT_TERMINAL_MICROPHONE and wTerminalType of EP-OUT to
UAC_OUTPUT_TERMINAL_SPEAKER for the UAC2 gadget.
Signed-off-by: Pavel Hofman <pavel.hofman@ivitera.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220131071813.7433-1-pavel.hofman@ivitera.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/function/f_uac2.c

@@ -203,7 +203,7 @@ static struct uac2_input_terminal_descriptor io_in_it_desc = {
 
 	.bDescriptorSubtype = UAC_INPUT_TERMINAL,
 	/* .bTerminalID = DYNAMIC */
-	.wTerminalType = cpu_to_le16(UAC_INPUT_TERMINAL_UNDEFINED),
+	.wTerminalType = cpu_to_le16(UAC_INPUT_TERMINAL_MICROPHONE),
 	.bAssocTerminal = 0,
 	/* .bCSourceID = DYNAMIC */
 	.iChannelNames = 0,
@@ -231,7 +231,7 @@ static struct uac2_output_terminal_descriptor io_out_ot_desc = {
 
 	.bDescriptorSubtype = UAC_OUTPUT_TERMINAL,
 	/* .bTerminalID = DYNAMIC */
-	.wTerminalType = cpu_to_le16(UAC_OUTPUT_TERMINAL_UNDEFINED),
+	.wTerminalType = cpu_to_le16(UAC_OUTPUT_TERMINAL_SPEAKER),
 	.bAssocTerminal = 0,
 	/* .bSourceID = DYNAMIC */
 	/* .bCSourceID = DYNAMIC */