spdk: pick up latest spdk

to silence the warnings reported by GCC-9

Signed-off-by: Kefu Chai <kchai@redhat.com>

diff --git a/src/spdk b/src/spdk
index fd292c568f72187e172b98074d7ccab362dae348..06d09c1108b16197ea985ae4d67867ed672a1e18 160000 (submodule)
--- a/src/spdk
+++ b/src/spdk
@@ -1 +1 @@
-Subproject commit fd292c568f72187e172b98074d7ccab362dae348
+Subproject commit 06d09c1108b16197ea985ae4d67867ed672a1e18