runtime: eliminate unnecessary type conversions

Automated refactoring produced using github.com/mdempsky/unconvert.

Change-Id: Iacf871a4f221ef17f48999a464ab2858b2bbaa90
Reviewed-on: https://go-review.googlesource.com/20071
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/src/runtime/traceback.go b/src/runtime/traceback.go
index 1717624..872b2ef 100644
--- a/src/runtime/traceback.go
+++ b/src/runtime/traceback.go
@@ -98,7 +98,7 @@
 			frame.arglen = 0
 			frame.argmap = nil
 		} else {
-			frame.pc = uintptr(fn.fn)
+			frame.pc = fn.fn
 			f := findfunc(frame.pc)
 			if f == nil {
 				print("runtime: unknown pc in defer ", hex(frame.pc), "\n")
@@ -174,7 +174,7 @@
 	printing := pcbuf == nil && callback == nil
 	_defer := gp._defer
 
-	for _defer != nil && uintptr(_defer.sp) == _NoArgs {
+	for _defer != nil && _defer.sp == _NoArgs {
 		_defer = _defer.link
 	}
 
@@ -600,7 +600,7 @@
 
 func callers(skip int, pcbuf []uintptr) int {
 	sp := getcallersp(unsafe.Pointer(&skip))
-	pc := uintptr(getcallerpc(unsafe.Pointer(&skip)))
+	pc := getcallerpc(unsafe.Pointer(&skip))
 	gp := getg()
 	var n int
 	systemstack(func() {