runtime: remove the dummy arg of getcallersp

getcallersp is intrinsified, and so the dummy arg is no longer
needed. Remove it, as well as a few dummy args that are solely
to feed getcallersp.

Change-Id: Ibb6c948ff9c56537042b380ac3be3a91b247aaa6
Reviewed-on: https://go-review.googlesource.com/109596
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/runtime/export_test.go

@@ -403,7 +403,7 @@ func LockOSCounts() (external, internal uint32) {
 //go:noinline
 func TracebackSystemstack(stk []uintptr, i int) int {
 	if i == 0 {
-		pc, sp := getcallerpc(), getcallersp(unsafe.Pointer(&stk))
+		pc, sp := getcallerpc(), getcallersp()
 		return gentraceback(pc, sp, 0, getg(), 0, &stk[0], len(stk), nil, nil, _TraceJumpStack)
 	}
 	n := 0