[v1.19] agent: remove --bpf-lb-proto-diff

[julianwiedmann]

Follow through on #39249 and remove the deprecated option.

[Surya-7890]

@julianwiedmann opened a PR, would like to get your opinion on it. Thanks!

[msune]

@Surya-7890 The BPF part is missing (ENABLE_SERVICE_PROTOCOL_DIFFERENTIATION) to fully remove --bpf-lb-proto-diff. Some (of the several) references to this flag:

• cilium/bpf/lib/lb.h

  Line 601 in 4b10336

  #if defined(ENABLE_SERVICE_PROTOCOL_DIFFERENTIATION)

• cilium/bpf/bpf_sock.c

  Line 269 in 4b10336

  #if defined(ENABLE_SERVICE_PROTOCOL_DIFFERENTIATION)

• cilium/bpf/tests/common.h

  Line 12 in 4b10336

  #define ENABLE_SERVICE_PROTOCOL_DIFFERENTIATION 1

• cilium/bpf/complexity-tests/54/bpf_xdp/6.txt

  Line 35 in 4b10336

  -DENABLE_SERVICE_PROTOCOL_DIFFERENTIATION=1

• ...