Update for kernel 5.11 binder header. am: 88f2587743 am: d7fc220aa3

Original change: https://android-review.googlesource.com/c/platform/system/libhwbinder/+/1592776

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I70da65510ec82a213da8ead3ee07109a773b107b
diff --git a/binder_kernel.h b/binder_kernel.h
index b8e00d3..64103bd 100644
--- a/binder_kernel.h
+++ b/binder_kernel.h
@@ -24,8 +24,4 @@
 
 #include <linux/android/binder.h>
 
-enum transaction_flags_ext {
-    TF_CLEAR_BUF = 0x20, /* clear buffer on txn complete */
-};
-
 #endif // ANDROID_HARDWARE_BINDER_KERNEL_H