configs/rock_pi_4: remove defconfig

This defconfig has been failing to build for several months, with
nobody stepping up to fix it. It's time to drop it.

See
https://lore.kernel.org/buildroot/20220806224338.0159e15c@windsurf/
for a notification on August 6, 2022 about the issues with this
defconfig.

Fixes:

  https://gitlab.com/buildroot.org/buildroot/-/jobs/3259671395

Cc: Suniel Mahesh <sunil@amarulasolutions.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

board/radxa/rockpi-4/extlinux.conf

@@ -1,4 +0,0 @@
-label RK3399_ROCK_PI_4 linux
-  kernel /Image
-  devicetree /rk3399-rock-pi-4.dtb
-  append earlycon=uart8250,mmio32,0xff1a0000 root=/dev/mmcblk1p4 rw rootwait

board/radxa/rockpi-4/genimage.cfg

@@ -1,39 +0,0 @@
-image boot.vfat {
-	vfat {
-		files = {
-			"Image",
-			"rk3399-rock-pi-4.dtb",
-			"extlinux"
-		}
-	}
-
-	size = 112M
-}
-
-image sdcard.img {
-	hdimage {
-		partition-table-type = "gpt"
-	}
-
-	partition loader1 {
-		image = "idbloader.img"
-		offset = 32K
-	}
-
-	partition loader2 {
-		image = "u-boot.itb"
-		offset = 8M
-	}
-
-	partition boot {
-		partition-type-uuid = F
-		bootable = "true"
-		image = "boot.vfat"
-		offset = 16M
-	}
-
-	partition rootfs {
-		partition-type-uuid = b921b045-1df0-41c3-af44-4c6f280d3fae
-		image = "rootfs.ext4"
-	}
-}

board/radxa/rockpi-4/post-build.sh

@@ -1,5 +0,0 @@
-#!/bin/sh
-
-BOARD_DIR="$(dirname $0)"
-
-install -m 0644 -D $BOARD_DIR/extlinux.conf $BINARIES_DIR/extlinux/extlinux.conf

board/radxa/rockpi-4/readme.txt

@@ -1,61 +0,0 @@
-RADXA ROCK_PI_4
-================
-https://rockpi.org/rockpi4
-
-ROCK Pi 4 is a Single Board Computer (SBC) from radxa. This guide is valid
-for the below models:
-- ROCK PI 4 Model A
-- ROCK PI 4 Model B
-- ROCK PI 4 Model C
-
-Build:
-======
-  $ make rock_pi_4_defconfig
-  $ make
-
-Files created in output directory
-=================================
-
-output/images
-
-├── bl31.elf
-├── boot.vfat
-├── extlinux
-├── idbloader.img
-├── Image
-├── rk3399-rock-pi-4.dtb
-├── rootfs.ext2
-├── rootfs.ext4 -> rootfs.ext2
-├── rootfs.tar
-├── sdcard.img
-├── u-boot.bin
-└── u-boot.itb
-
-Creating bootable SD card:
-==========================
-
-Simply invoke (as root)
-
-sudo dd if=output/images/sdcard.img of=/dev/sdX && sync
-
-Where X is your SD card device.
-
-Booting:
-========
-
-Serial console:
----------------
-RockPi4 has a 40-pin GPIO header. The pin layout is as follows:
-
-pin 6:  gnd
-pin 8:  tx
-pin 10: rx
-
-Baudrate for this board is 1500000.
-
-Login:
-------
-Enter 'root' as login user, and the prompt is ready.
-
-Wiki link:
-https://wiki.amarulasolutions.com/bsp/rockchip/rk3399/rock-pi-4.html