cmd/cgo: add support for GOARCH=mips{,le}

Change-Id: I47c6867fc653c8388ad32e210a8027baa592eda3
Reviewed-on: https://go-review.googlesource.com/31483
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/cmd/cgo/main.go

@@ -143,6 +143,8 @@ var ptrSizeMap = map[string]int64{
 	"amd64":    8,
 	"arm":      4,
 	"arm64":    8,
+	"mips":     4,
+	"mipsle":   4,
 	"mips64":   8,
 	"mips64le": 8,
 	"ppc64":    8,
@@ -156,6 +158,8 @@ var intSizeMap = map[string]int64{
 	"amd64":    8,
 	"arm":      4,
 	"arm64":    8,
+	"mips":     4,
+	"mipsle":   4,
 	"mips64":   8,
 	"mips64le": 8,
 	"ppc64":    8,