fix: wrong function name

``` error: implicit declaration of function 'flex_enc32le_aligned'; did you mean 'sph_enc32le_aligned'? [-Wimplicit-function-declaration] ``` Looking at the Kylacoin source code, this is incorrect. https://github.com/kylacoin/kylacoin/blob/fe6f2ad64ffcc4eae213c378336cf574f68b8672/src/crypto/flex/sph/keccak.c#L1697