Fixed -Wshadow warning from GCC

[orbitcowboy]

This commit fixes

keccak.cpp: In member function ‘void Keccak::processBlock(const void*)’:
keccak.cpp:155:16: warning: declaration of ‘one’ shadows a previous local [-Wshadow]
  155 |       uint64_t one = m_hash[j];
      |                ^~~
keccak.cpp:122:14: note: shadowed declaration is here
  122 |     uint64_t one;
      |              ^~~