Update to v4.19 kernel headers.

Test: Builds and boots.
Change-Id: I99a9ed79666e143b47f02ca4e59eed94f69b7e4a
(cherry picked from commit a981e2e52e2e95a65fa9c9b6fb16dcb4c83dd576)
diff --git a/libc/kernel/uapi/linux/dcbnl.h b/libc/kernel/uapi/linux/dcbnl.h
index 2fe4cce..d1f2eba 100644
--- a/libc/kernel/uapi/linux/dcbnl.h
+++ b/libc/kernel/uapi/linux/dcbnl.h
@@ -71,6 +71,13 @@
   __u64 requests[IEEE_8021QAZ_MAX_TCS];
   __u64 indications[IEEE_8021QAZ_MAX_TCS];
 };
+#define IEEE_8021Q_MAX_PRIORITIES 8
+#define DCBX_MAX_BUFFERS 8
+struct dcbnl_buffer {
+  __u8 prio2buffer[IEEE_8021Q_MAX_PRIORITIES];
+  __u32 buffer_size[DCBX_MAX_BUFFERS];
+  __u32 total_size;
+};
 #define CEE_DCBX_MAX_PGS 8
 #define CEE_DCBX_MAX_PRIO 8
 struct cee_pg {
@@ -170,6 +177,7 @@
   DCB_ATTR_IEEE_MAXRATE,
   DCB_ATTR_IEEE_QCN,
   DCB_ATTR_IEEE_QCN_STATS,
+  DCB_ATTR_DCB_BUFFER,
   __DCB_ATTR_IEEE_MAX
 };
 #define DCB_ATTR_IEEE_MAX (__DCB_ATTR_IEEE_MAX - 1)