Bug#982308: linux-image-arm64: revert DTB overlay config

[Jiri Kastner <cz172638@gmail.com>]

Package: linux-image-arm64
Version: 5.10.0
Severity: normal

Dear Maintainer,

removal of kernel config options for overlay is causing me
troubles to play with dtb without reboot.

for example jtag/swd/trace pins are usually muxed with gpio/sdmmc/lcd
on arm devices.
to be able debug or trace i need to recompile dtb and reboot. and having
such pins permanently exposed in dtb is not good idea for production
kernels.

-- System Information:
Debian Release: bullseye/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: arm64 (aarch64)

Kernel: Linux 5.9.0-0.bpo.5-amd64 (SMP w/2 CPU threads)
Locale: LANG=C, LC_CTYPE=C.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /bin/dash
Init: unable to detect