Is this the right place for my bug report?
The /proc/config.gz on my RPi doesn't match defconfigs from https://github.com/raspberrypi/linux. And the Linux kernel is shipped via firmware update, instead of a raspbian package. So I think this is the right place to report this issue.

Describe the bug
I want to make use of USB CDC-NCM (for networking) and TCM (for storage) gadget functions on RPi. However the Linux configuration does not enable aforementioned modules.

To reproduce

root@raspberrypi:~# modprobe configs
root@raspberrypi:~# zgrep USB_F_ /proc/config.gz
CONFIG_USB_F_ACM=m
CONFIG_USB_F_SS_LB=m
CONFIG_USB_F_SERIAL=m
CONFIG_USB_F_OBEX=m
CONFIG_USB_F_ECM=m
CONFIG_USB_F_SUBSET=m
CONFIG_USB_F_RNDIS=m
CONFIG_USB_F_MASS_STORAGE=m
CONFIG_USB_F_UAC2=m
CONFIG_USB_F_UVC=m
CONFIG_USB_F_MIDI=m
CONFIG_USB_F_HID=m
CONFIG_USB_F_PRINTER=m

Expected behaviour
expected CONFIG_USB_F_NCM=m and CONFIG_USB_F_TCM=m

Actual behaviour
CONFIG_USB_F_TCM and CONFIG_USB_F_TCM are not configured.

System

• Which OS and version (cat /etc/rpi-issue)?

  root@raspberrypi:~# cat /etc/rpi-issue
  Raspberry Pi reference 2021-10-30
  Generated using pi-gen, https://github.com/RPi-Distro/pi-gen, 288b21fc27e128ea6b330777aca68e0061ebf4fe, stage2
  

• Which firmware version (vcgencmd version)?

  root@raspberrypi:~# vcgencmd version
  Oct 29 2021 10:49:08
  Copyright (c) 2012 Broadcom
  version b8a114e5a9877e91ca8f26d1a5ce904b2ad3cf13 (clean) (release) (start)
  

• Which kernel version (uname -a)?

  root@raspberrypi:~# uname -a
  Linux raspberrypi 5.10.63-v7+ #1459 SMP Wed Oct 6 16:41:10 BST 2021 armv7l GNU/Linux