cmd/6a: include MOVQL opcode.
cmd/6a: include MOVQL opcode.

LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://codereview.appspot.com/54660046

h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang