Revert "llc: Improve setsockopt() handling of malformed user input"

This reverts commit 981d647c which is
commit 1465036b 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: I33d7231dae0f23df8750010315515440e2687a9c
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>