bpf: Fix non-static bpf_func_proto struct definitions

This patch does two things:

1) Marks the dynptr bpf_func_proto structs that were added in [1]
   as static, as pointed out by the kernel test robot in [2].

2) There are some bpf_func_proto structs marked as extern which can
   instead be statically defined.

  [1] https://lore.kernel.org/bpf/20220523210712.3641569-1-joannelkoong@gmail.com/
  [2] https://lore.kernel.org/bpf/62ab89f2.Pko7sI08RAKdF8R6%25lkp@intel.com/



Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220616225407.1878436-1-joannelkoong@gmail.com