runtime: remove go prefix from a few routines

They are no longer needed now that C is gone.

goatoi -> atoi
gofuncname/funcname -> funcname/cfuncname
goroundupsize -> already existing roundupsize

Change-Id: I278bc33d279e1fdc5e8a2a04e961c4c1573b28c7
Reviewed-on: https://go-review.googlesource.com/2154
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>
diff --git a/src/runtime/panic.go b/src/runtime/panic.go
index ff1ef2a..2e3ed3f 100644
--- a/src/runtime/panic.go
+++ b/src/runtime/panic.go
@@ -130,7 +130,7 @@
 		if defersc >= uintptr(len(m)) {
 			break
 		}
-		siz := goroundupsize(totaldefersize(i))
+		siz := roundupsize(totaldefersize(i))
 		if m[defersc] < 0 {
 			m[defersc] = int32(siz)
 			continue
@@ -173,7 +173,7 @@
 	}
 	if d == nil {
 		// Allocate new defer+args.
-		total := goroundupsize(totaldefersize(uintptr(siz)))
+		total := roundupsize(totaldefersize(uintptr(siz)))
 		d = (*_defer)(mallocgc(total, deferType, 0))
 	}
 	d.siz = siz