Entity-Manager: Delete unused define

This define was removed in patch 28633.

Change-Id: Iab7d98ef018560f5928f65c56bebc893a001ec58
Signed-off-by: James Feist <james.feist@linux.intel.com>
diff --git a/recipes-phosphor/configuration/entity-manager_git.bb b/recipes-phosphor/configuration/entity-manager_git.bb
index 50ab0a4..19b5aed 100644
--- a/recipes-phosphor/configuration/entity-manager_git.bb
+++ b/recipes-phosphor/configuration/entity-manager_git.bb
@@ -21,5 +21,5 @@
 S = "${WORKDIR}/git/"
 inherit cmake systemd
 
-EXTRA_OECMAKE = "-DYOCTO=1 -DUSE_OVERLAYS=0"
+EXTRA_OECMAKE = "-DYOCTO=1"