doc: user --recursive in directions for cloning SPDK repo

As oppsoed to having steps to change to the SPDK dir and use
git submodule command to init submodules.

Signed-off-by: paul luse <paul.e.luse@intel.com>
Change-Id: I4b0d9fb242cfd41946a2cbba9e6de76db6374612
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/14341
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Krzysztof Karas <krzysztof.karas@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>

doc/getting_started.md

@@ -3,9 +3,7 @@
 ## Getting the Source Code {#getting_started_source}
 
 ~~~{.sh}
-git clone https://github.com/spdk/spdk
+git clone https://github.com/spdk/spdk --recursive
-cd spdk
-git submodule update --init
 ~~~
 
 ## Installing Prerequisites {#getting_started_prerequisites}

doc/nvmf.md

@@ -130,11 +130,9 @@ After cloning SPDK repo and initialize submodules, FC LLD library is built which
 the fc transport.
 
 ~~~{.sh}
-git clone https://github.com/spdk/spdk spdk
+git clone https://github.com/spdk/spdk --recursive
 git clone https://github.com/ecdufcdrvr/bcmufctdrvr fc
-cd spdk
+cd fc
-git submodule update --init
-cd ../fc
 make DPDK_DIR=../spdk/dpdk/build SPDK_DIR=../spdk
 cd ../spdk
 ./configure --with-fc=../fc/build

doc/nvmf_multipath_howto.md

@@ -8,13 +8,12 @@ path load balancing.
 
 Clone the repo:
 ~~~{.sh}
-git clone https://github.com/spdk/spdk
+git clone https://github.com/spdk/spdk --recursive
 ~~~
 
 Configure and build SPDK:
 ~~~{.sh}
 cd spdk/
-git submodule update --init
 ./configure
 make -j16
 ~~~