[edk2-platforms: PATCH] Readme.md: Change way of cloning edk2 repo

["Wang, Jian J" <jian.j.wang@intel.com>]

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=1910

'--recursive' in cloning edk2 repo might cause failure on machine
behind proxy. It's not actually necessary for edk2. This patch removed
it from git command. A separate command

   $ git submodule update --init

is added to retrieve repo specified via submodule.

Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
---
 Readme.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Readme.md b/Readme.md
index e203795d47..63e59f60b4 100644
--- a/Readme.md
+++ b/Readme.md
@@ -83,7 +83,8 @@ target-specific binutils. These are included with any prepackaged GCC toolchain
    1. [edk2-non-osi](https://github.com/tianocore/edk2-non-osi) (if building
       platforms that need it)
    ```
-   $ git clone https://github.com/tianocore/edk2.git --recursive
+   $ git clone https://github.com/tianocore/edk2.git
+   $ git submodule update --init
    ...
    $ git clone https://github.com/tianocore/edk2-platforms.git
    ...
-- 
2.17.1.windows.2