[3.13-stable only] Revert "ARM: net: delegate filter to kernel interpreter when imm_offset() return value can't fit into 12bits."

This reverts commit a39d787c.

Not suitable for 3.13 (no bpf_jit_binary_free).

Cc: Brad Figg <brad.figg@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>