check string against nullptr

Bug: 245651185
Bug: 244468573
Test: boot, fuzzer
Change-Id: I479341e6e95720303bcd542dbeb50c4383d59cc6
diff --git a/media/ndk/NdkMediaFormat.cpp b/media/ndk/NdkMediaFormat.cpp
index a95e874..c0de4e4 100644
--- a/media/ndk/NdkMediaFormat.cpp
+++ b/media/ndk/NdkMediaFormat.cpp
@@ -332,6 +332,9 @@
     if (name == nullptr) {
         return;
     }
+    if (value == nullptr) {
+        return;
+    }
     // AMessage::setString() makes a copy of the string
     format->mFormat->setString(name, value, strlen(value));
 }