build_package.sh: Split submodule init vs update operations

In the hope that it may improve retry-ability of the update part.

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: Iab7f9ef402c5ac2de2e3d0fea378a4bbf19a9037
(cherry picked from commit fc1cf6be4dc68a031b53bd5d98fb0aee5e90c188)
diff --git a/script/build_package.sh b/script/build_package.sh
index fe602fe..38f2be8 100755
--- a/script/build_package.sh
+++ b/script/build_package.sh
@@ -1254,7 +1254,8 @@
 	pushd "$spm_root"
 	# Check if submodules need initialising
 	if git submodule status | grep '^-'; then
-		retry git submodule update --init
+		git submodule init
+		retry git submodule update
 	fi
 	popd