Fixes a compilation issue on MacOSX.

The issue appears with -Werror applied, might need to be handled
for other platforms, but I haven't heard of any issues with them.

error: sizeof on array function parameter will return size of 'uint64_t *'
      (aka 'unsigned long long *') instead of 'uint64_t [8]' [-Werror,-Wsizeof-array-argument]

The reason it may cause issues on other platforms is that the pointers may not have a 64bit width in some cases so even on platforms where this doesn't throw an error it may not always resolve to the expected 8.