linux-yocto/4.18: integrate CVE fixes

linux-yocto/4.18: integrate CVE fixes

Integrating the following CVE fixes into the 4.18 tree:

  e78a46f375fe cdrom: fix improper type cast, which can leat to information leak.
  4815231b9b65 btrfs: tree-checker: Verify block_group_item
  6dfe2fe5dd52 btrfs: Introduce mount time chunk <-> dev extent mapping check
  ccd06dcdc11b btrfs: Verify that every chunk has corresponding block group at mount time
  7cf70b1e759a btrfs: Check that each block group has corresponding chunk at mount time
  166bbd6ff86b btrfs: validate type when reading a chunk
  ecf31c809599 ip: frags: fix crash in ip_do_fragment()
  02fc22c5eb30 ip: use rb trees for IP frag queue.
  72dd075ee367 net: modify skb_rbtree_purge to return the truesize of all purged skbs.
  7a9f904c49aa ip: discard IPv4 datagrams with overlapping segments.
  abea198657b7 f2fs: fix to do sanity check with i_extra_isize
  408c425c41e4 f2fs: fix to do sanity check with node footer and iblocks
  5e4ccef734c3 f2fs: fix to do sanity check with user_block_count

(From OE-Core rev: e09309a50dd5f4d8fc75915a5f2e97a16603aa9a)

Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>