use store64() for the same purpose (to store a 64bit integer as a byte array in little-endian order)

[francescomedina]

I notice that the target line computes a simple store of a 64bit integer as a byte array in little-endian order. The store64() was created with this purpose and is already called in other functions. Since both ways produce the same output with same elaboration time (on release mode) in order to have a more readable code this contribution was introduced.

@mberry

[mberry]

Nice catch.