zenfone9: Build libstagefright_softomx_plugin VNDK libraries

- E vndksupport: Could not load libstagefright_softomx_plugin.so from default namespace: dlopen failed: library "libstagefright_softomx_plugin.so" not found.

Change-Id: I7c9750250bd519329ded3ad77ab7bee1af911e35
Signed-off-by: Jackeagle <jackeagle102@gmail.com>
diff --git a/device.mk b/device.mk
index 96aba00..12ef63f 100755
--- a/device.mk
+++ b/device.mk
@@ -238,7 +238,8 @@
     libstagefright_softomx.vendor \
     libstagefrighthw \
     libplatformconfig \
-    libsqlite.vendor
+    libsqlite.vendor \
+    libstagefright_softomx_plugin.vendor
 
 $(call inherit-product, hardware/qcom-caf/sm8450/media/product.mk)