x/sys/unix: asm_solaris_amd64.s: wrong argument size 64; expected $...-88

[mikioh]

GOOS=solaris go tool vet warns the following:

asm_solaris_amd64.s:13: [amd64] sysvicall6: wrong argument size 64; expected $...-88
asm_solaris_amd64.s:16: [amd64] rawSysvicall6: wrong argument size 64; expected $...-88

[gopherbot]

CL https://golang.org/cl/43211 mentions this issue.