sha3.c: refactor backends so they only implement permute_n()

i verified that (gcc, at least) does constant propagation and inlines
permute_n_<backend> and that this change does not affect performance.

bench results, before:
  pabs@flex:~/git/sha3/tests/bench> ./bench
  info: cpucycles: version=20240318 implementation=amd64-pmc persecond=4800000000
  info: backend=avx512 num_trials=100000 src_lens=64,256,1024,4096,16384 dst_lens=32
  function,dst_len,64,256,1024,4096,16384
  sha3_224,28,15.4,7.8,7.8,7.1,7.0
  sha3_256,32,15.5,7.8,7.8,7.6,7.4
  sha3_384,48,15.5,11.7,9.8,9.8,9.7
  sha3_512,64,15.6,15.5,14.6,13.9,13.9
  shake128,32,15.5,7.8,6.9,6.2,6.1
  shake256,32,15.5,7.8,7.9,7.6,7.4

bench results, after change:
  pabs@flex:~/git/sha3/tests/bench> ./bench
  info: cpucycles: version=20240318 implementation=amd64-pmc persecond=4800000000
  info: backend=avx512 num_trials=100000 src_lens=64,256,1024,4096,16384 dst_lens=32
  function,dst_len,64,256,1024,4096,16384
  sha3_224,28,15.4,7.8,7.8,7.1,7.0
  sha3_256,32,15.6,7.8,7.8,7.6,7.4
  sha3_384,48,15.6,11.7,9.8,9.8,9.7
  sha3_512,64,15.6,15.5,14.6,13.8,13.8
  shake128,32,15.6,7.9,6.9,6.2,6.1
  shake256,32,15.7,7.9,7.9,7.6,7.4

0 files changed, 0 insertions, 0 deletions