Update to v6.3 kernel headers.

Kernel headers coming from:

Git: https://android.googlesource.com/kernel/common/
Branch: android-mainline
Tag: android-mainline-6.3

Test: Bionic unit tests pass.
Change-Id: I5270ef291a77343e47ef3a5fbd02b8cacf218ec5
diff --git a/libc/kernel/uapi/linux/snmp.h b/libc/kernel/uapi/linux/snmp.h
index e3d6ee3..ea3f058 100644
--- a/libc/kernel/uapi/linux/snmp.h
+++ b/libc/kernel/uapi/linux/snmp.h
@@ -87,6 +87,8 @@
   ICMP_MIB_OUTADDRMASKS,
   ICMP_MIB_OUTADDRMASKREPS,
   ICMP_MIB_CSUMERRORS,
+  ICMP_MIB_RATELIMITGLOBAL,
+  ICMP_MIB_RATELIMITHOST,
   __ICMP_MIB_MAX
 };
 #define __ICMPMSG_MIB_MAX 512
@@ -97,6 +99,7 @@
   ICMP6_MIB_OUTMSGS,
   ICMP6_MIB_OUTERRORS,
   ICMP6_MIB_CSUMERRORS,
+  ICMP6_MIB_RATELIMITHOST,
   __ICMP6_MIB_MAX
 };
 #define __ICMP6MSG_MIB_MAX 512