Update to v6.4 kernel headers.

Kernel headers coming from:

Git: https://android.googlesource.com/kernel/common/
Branch: android-mainline
Tag: android-mainline-6.4

Test: Bionic unit tests pass.
Change-Id: I991f8eaa2b272a464166addb13e6bdc63734444d
diff --git a/libc/kernel/uapi/linux/prctl.h b/libc/kernel/uapi/linux/prctl.h
index 6ad1c04..ccab000 100644
--- a/libc/kernel/uapi/linux/prctl.h
+++ b/libc/kernel/uapi/linux/prctl.h
@@ -189,4 +189,7 @@
 #define PR_GET_MDWE 66
 #define PR_SET_VMA 0x53564d41
 #define PR_SET_VMA_ANON_NAME 0
+#define PR_GET_AUXV 0x41555856
+#define PR_SET_MEMORY_MERGE 67
+#define PR_GET_MEMORY_MERGE 68
 #endif