generic/4.0: fix error during kernel patch application

generic/4.0: fix error during kernel patch application

Commit 5168c9a5702648eb690d32ec821647aca80aeba9 introduced a regression
during patch application on the 4.0 kernel. Some of the patched content
doesn't match the actual code, therefore leading to the following error:
  Applying patch generic/667-ipv6-Fixed-source-specific-default-route-handling.patch
  patching file net/ipv6/ip6_output.c
  Hunk #1 FAILED at 886.
  1 out of 1 hunk FAILED -- rejects in file net/ipv6/ip6_output.c
  patching file net/ipv6/route.c
  Hunk #1 succeeded at 2247 (offset 2 lines).
  Patch generic/667-ipv6-Fixed-source-specific-default-route-handling.patch does not apply (enforce with -f)

This change just adapts the actual patch to fix what is in kernel 4.0
and make it apply cleanly.

Signed-off-by: Mathieu Olivari <mathieu@codeaurora.org>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@45705 3c298f89-4303-0410-b956-a3cf2f4a3e73