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/blkzoned.h b/libc/kernel/uapi/linux/blkzoned.h
index c071c98..eaff1d8 100644
--- a/libc/kernel/uapi/linux/blkzoned.h
+++ b/libc/kernel/uapi/linux/blkzoned.h
@@ -50,7 +50,7 @@
   __u32 nr_zones;
   __u8 reserved[4];
   struct blk_zone zones[0];
-} __packed;
+};
 struct blk_zone_range {
   __u64 sector;
   __u64 nr_sectors;