Fix bufferpool

Fix bufferpool carsh sporadically on invalidation. use android::sp
instead of android::wp for caching IObserver hidl interface.

Bug: 112203066
Change-Id: I69aafa11cc617f9ae36cce88283a3294fcab9bbd
diff --git a/media/bufferpool/2.0/Accessor.cpp b/media/bufferpool/2.0/Accessor.cpp
index f264501..57b4609 100644
--- a/media/bufferpool/2.0/Accessor.cpp
+++ b/media/bufferpool/2.0/Accessor.cpp
@@ -113,6 +113,10 @@
     return sConnectionDeathRecipient;
 }
 
+void Accessor::createInvalidator() {
+    Accessor::Impl::createInvalidator();
+}
+
 // Methods from ::android::hardware::media::bufferpool::V2_0::IAccessor follow.
 Return<void> Accessor::connect(
         const sp<::android::hardware::media::bufferpool::V2_0::IObserver>& observer,