x86-64: fix EVEX encoding for memory operands with zero-masking
x86-64: fix EVEX encoding for memory operands with zero-masking

pombredanne/PeachPy,lemire/PeachPy,shaunstanislaus/PeachPy,silky/PeachPy,adamzhz/PeachPy,utensil-star/PeachPy