configs/rock_pi_n8: remove defconfig, broken

This defconfig no longer builds:

  https://gitlab.com/buildroot.org/buildroot/-/jobs/11026769867

It has been broken for at least 2 months:

  https://gitlab.com/buildroot.org/buildroot/-/jobs?name=T%3Drock_pi_n8&kind=BUILD

This defconfig was maintained by Suniel Mahesh, but his e-mail at
Amarula is bouncing, so basically this defconfig is unmaintained.

Unless a fix is provided, this defconfig will be removed.

Fixes:

  https://gitlab.com/buildroot.org/buildroot/-/jobs/11026769867

Cc: Adam Duskett <adam.duskett@amarulasolutions.com>
Cc: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Cc: Jagan Teki <jagan@amarulasolutions.com>
Cc: Meena Murthy <meena.murthy@amarulasolutions.com>
Cc: Michael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Arnout Vandecappelle <arnout@rnout.be>
(cherry picked from commit 883ef369e4)
Signed-off-by: Titouan Christophe <titouan.christophe@mind.be>

.checkpackageignore

@@ -52,7 +52,6 @@ board/orangepi/orangepi-zero/patches/linux/0004-ARM-dts-orange-pi-zero-enable-ua
 board/qemu/aarch64-sbsa/assemble-flash-images Shellcheck
 board/qemu/x86/post-build.sh Shellcheck
 board/qemu/x86_64/post-build.sh Shellcheck
-board/radxa/rockpi-n8/post-build.sh Shellcheck
 board/raspberrypi/post-build.sh Shellcheck
 board/raspberrypi/post-image.sh Shellcheck
 board/roseapplepi/patches/uboot/0001-compiler-.h-sync-include-linux-compiler-.h-with-Linu.patch lib_patch.Upstream
@@ -180,7 +179,6 @@ configs/pc_x86_64_efi_defconfig lib_defconfig.ForceCheckHash
 configs/pine64_defconfig lib_defconfig.ForceCheckHash
 configs/pine64_pinecube_defconfig lib_defconfig.ForceCheckHash
 configs/pine64_star64_defconfig lib_defconfig.ForceCheckHash
-configs/rock_pi_n8_defconfig lib_defconfig.ForceCheckHash
 configs/roseapplepi_defconfig lib_defconfig.ForceCheckHash
 configs/s6lx9_microboard_defconfig lib_defconfig.ForceCheckHash
 configs/sipeed_lichee_rv_defconfig lib_defconfig.ForceCheckHash