syscall: remove //sysnb comment generating Setreuid for linux/arm64

CL 210639 moved the //sysnb for Setreuid from syscall_linux_$GOARCH.go
to syscall_linux.go but forgot to remove the comment from
syscall_linux_arm64.go which leads to Setreuid being generated twice for
linux/arm64. Remove that //sysnb comment to avoid this.

Change-Id: I2c8ad95f786530ca964685b0a4fe463c64764307
Reviewed-on: https://go-review.googlesource.com/c/go/+/350531
Trust: Tobias Klauser <[email protected]>
Run-TryBot: Tobias Klauser <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>

Author: tklauser

src/syscall/syscall_linux_arm64.go

@@ -42,7 +42,6 @@ func EpollCreate(size int) (fd int, err error) {
 //sys	Setfsgid(gid int) (err error)
 //sys	Setfsuid(uid int) (err error)
 //sysnb	setrlimit(resource int, rlim *Rlimit) (err error)
-//sysnb	Setreuid(ruid int, euid int) (err error)
 //sys	Shutdown(fd int, how int) (err error)
 //sys	Splice(rfd int, roff *int64, wfd int, woff *int64, len int, flags int) (n int64, err error)