Revert "bpf: consider that tail calls invalidate packet pointers"

This reverts commit f1692ee2 which is
commit 1a4607ff upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: Ie3fb4b43ba1abcbc9f7977c54c8fed847f7455c7
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>