Fix issue with fp512bn on 32 to bit OS
Fix issue with fp512bn on 32 to bit OS

Signed-off-by: Kirk Baird <7e55c1b2a8e4d9d0e3a363b1e21c0cd98476db27@outlook.com>

miracl/amcl,miracl/amcl,miracl/amcl,miracl/amcl,miracl/amcl,miracl/amcl,miracl/amcl,miracl/amcl,miracl/amcl,miracl/amcl