Remove redefinition of uapi constant added in R.

Test: treehugger
Change-Id: If0ef9c36b2f54eb59d222dedc6bf575d46c9db1d
diff --git a/libcutils/ashmem-dev.cpp b/libcutils/ashmem-dev.cpp
index 6a27f9a..5e01da9 100644
--- a/libcutils/ashmem-dev.cpp
+++ b/libcutils/ashmem-dev.cpp
@@ -44,9 +44,6 @@
 #include <android-base/strings.h>
 #include <android-base/unique_fd.h>
 
-/* Will be added to UAPI once upstream change is merged */
-#define F_SEAL_FUTURE_WRITE 0x0010
-
 /*
  * The minimum vendor API level at and after which it is safe to use memfd.
  * This is to facilitate deprecation of ashmem.