This updates the Go function declarations to match race_amd64.s.

Change-Id: I2b541a6b335ce732f4c31652aa615240ce7bb1c3
Reviewed-on: https://go-review.googlesource.com/c/go/+/177397
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Austin Clements <austin@google.com>