Merge branch 'bpf-optimize-neg-sums'

Jakub Kicinski says:

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This set adds an optimization run to the NFP jit to turn ADD and SUB
instructions with negative immediate into the opposite operation with
a positive immediate. NFP can fit small immediates into the instructions
but it can't ever fit negative immediates. Addition of small negative
immediates is quite common in BPF programs for stack address calculations,
therefore this optimization gives us non-negligible savings in instruction
count (up to 4%).
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>