infra/download_source: update the steps for installing repo

The repo tool, when installed using package manager, could install an
older version of the repo tool. So point to the manual steps for
installing the repo tool.
Signed-off-by: Thomas Abraham <thomas.abraham@arm.com>
Change-Id: I56dd4f85d8f113ce683de1737afdb02225821f7a

docs/infra/common/download-sources.rst

@@ -13,8 +13,8 @@ higher with 64GB of free disk space and 32GB of RAM is minimum requirement to
 sync and build the platform software stack. 48GB of RAM is recommended though.
 
 
-Repo tool setup
----------------
+Git and Repo tool setup
+-----------------------
 
 The Neoverse RD software stack is available in multiple git repositories. In
 order to simplify downloading the software stack, `repo tool
@@ -42,15 +42,10 @@ can be used. This section explains the procedure to setup git and repo tool.
     git config --global user.name "<your-name>"
     git config --global user.email "<your-email@example.com>"
 
-- Install the repo tool either `manually
-  <https://source.android.com/setup/develop#installing-repo>`_ or through apt
-  package:
-
-  ::
-
-    sudo apt install repo
+- Install the repo tool by following `these
+  <https://source.android.com/setup/develop#installing-repo>`_ instructions.
 
-This completes the setup of the repo tool.
+This completes the setup of git and repo tool.
 
 
 Platform Manifest Names