sha: merge K[] for sha256 and 512

function                                             old     new   delta
sha_K                                                  -     640    +640
sha256_process_block64                               440     425     -15
sha512_process_block128                             1336    1283     -53
K512_lo                                              320       -    -320
K256                                                 320       -    -320
------------------------------------------------------------------------------
(add/remove: 1/2 grow/shrink: 0/2 up/down: 640/-708)          Total: -68 bytes

1 file changed