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/include/bits/glibc-syscalls.h b/libc/include/bits/glibc-syscalls.h
index 79f7da0..3b4b5bf 100644
--- a/libc/include/bits/glibc-syscalls.h
+++ b/libc/include/bits/glibc-syscalls.h
@@ -909,6 +909,9 @@
 #if defined(__NR_riscv_flush_icache)
   #define SYS_riscv_flush_icache __NR_riscv_flush_icache
 #endif
+#if defined(__NR_riscv_hwprobe)
+  #define SYS_riscv_hwprobe __NR_riscv_hwprobe
+#endif
 #if defined(__NR_rmdir)
   #define SYS_rmdir __NR_rmdir
 #endif