Remove manifest file

The manifest is now maintained in a separate repo to make it easier for
developers to change the source repo version without affecting the build
scripts repo.
Signed-off-by: Grant Likely <grant.likely@arm.com>

README.rst

 .. SPDX-License-Identifier: GPL-2.0+
 .. Copyright (C) Arm Limited, 2020
 
-U-Boot Image Builder Manifest
-=============================
+U-Boot w/ Trusted Firmware Image Builder
+========================================
 
-This is a simple tool for build Arm firmware images from U-Boot,
-Trusted Firmware A, and the Linux devicetree repo. It uses the
-git 'repo' tool to clone a copy of each project and a Makefile
-to build for various Arm targets.
+This is a simple tool for build Arm firmware images from U-Boot, Trusted
+Firmware A, and the Linux devicetree repo.
+It uses the git 'repo' tool to clone a copy of each project and a Makefile to
+build for various Arm targets.
 
 Using this tool
 ---------------
-This tool uses the git 'repo' tool to build firmware.
-Install repo first
+It is best to use this tool with the `u-boot-manifest` repo to fetch all the required source repositories.
+Use the git `repo` tool to fetch all the projects listed in the manifest and
+create the required symlinks.
+Install repo first.
+Most linux distros have repo packaged.
 
 To initialize the build environment, create a new working directory
 and run the repo init command::

default.xml

-<manifest>
-	<remote name="marvell" fetch="https://github.com/MarvellEmbeddedProcessors"/>
-	<remote name="github" fetch="https://github.com/"/>
-	<remote name="kernel.org" fetch="https://git.kernel.org/pub/scm/linux/kernel/git"/>
-	<remote name="tf.org" fetch="https://git.trustedfirmware.org/TF-A"/>
-	<remote name="linaro-ilias" fetch="https://git.linaro.org/people/ilias.apalodimas"/>
-
-	<default revision="refs/heads/master" remote="github" sync-j="4"/>
-
-	<project name="glikely/u-boot-manifest" path="scripts">
-		<linkfile src="top.mk" dest="Makefile"/>
-		<linkfile src="buildall.sh" dest="buildall.sh"/>
-	</project>
-
-	<!-- OP-TEE -->
-	<project path="optee_os"	remote="github" name="apalos/optee_os" revision="stmm_pr"/>
-
-	<!-- EDK2 for StandaloneMM -->
-	<project name="edk2"		remote="linaro-ilias" revision="stmm_ffa" sync-s="true"/>
-	<project name="edk2-platforms"	remote="linaro-ilias" revision="stmm_rpmb_ffa"/>
-
-	<project name="trusted-firmware-a" remote="tf.org"/>
-	<project name="u-boot/u-boot" path="u-boot"/>
-	<project name="devicetree/devicetree-rebasing.git" path="devicetree-rebasing" remote="kernel.org"/>
-
-	<!-- Platform specific source and binaries -->
-	<project name="binaries-marvell" remote="marvell" path="binaries-marvell" revision="refs/heads/binaries-marvell-armada-18.12"/>
-	<project name="mv-ddr-marvell" remote="marvell" path="mv-ddr" revision="refs/heads/mv_ddr-armada-atf-mainline"/>
-</manifest>
-