Revert "net: support marking accepting TCP sockets"

This reverts commit d3ec24d4e722992951f9218216255237c5d48bd9.
Revert "net: add a sysctl to reflect the fwmark on replies"

This reverts commit 25b27bae0aadbcc8b96dc31f1c18492bf8a35a23.
Revert "net: ipv6: autoconf routes into per-device tables"

This reverts commit f3f6a24790f2bd96ccd49d610eb999fd50a97c92.
Revert "net: ipv6: ping: Use socket mark in routing lookup"

This reverts commit b465ef5cb0a832020102677b195f02b6a89c5a39.