Update to v5.18 kernel headers.

Kernel headers coming from:

Git: https://android.googlesource.com/kernel/common/
Branch: android-mainline
Tag: android-mainline-5.18

The file bionic/libc/kernel/uapi/linux/android/binder.h had a bug
in the original 5.18 kernel headers. This was fixed upstream, so
add a comment to the structure but leave the incorrect field the
same as the 5.17 kernel headers.

Bug: 234125620

Test: Builds.
Test: All bionic unit tests pass on a coral device.
Test: Able to log in to wembley system.
Change-Id: Ia72cafbe71fd894c599e15aa5334d7bbcbe74778
diff --git a/libc/kernel/uapi/linux/gtp.h b/libc/kernel/uapi/linux/gtp.h
index 3b9416e..20bc3d6 100644
--- a/libc/kernel/uapi/linux/gtp.h
+++ b/libc/kernel/uapi/linux/gtp.h
@@ -23,6 +23,7 @@
   GTP_CMD_NEWPDP,
   GTP_CMD_DELPDP,
   GTP_CMD_GETPDP,
+  GTP_CMD_ECHOREQ,
   GTP_CMD_MAX,
 };
 enum gtp_version {