libgo: update x/sys/cpu to add all GOARCHes supported by gccgo

CL 237897 added additional GOARCHes supported by gccgo to x/sys/cpu.

Change-Id: If1129bf404fd3fbf18ae4400c1445b79f4671c46
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/238038
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/libgo/go/golang.org/x/sys/cpu/byteorder.go b/libgo/go/golang.org/x/sys/cpu/byteorder.go
index da6b9e4..74116e9 100644
--- a/libgo/go/golang.org/x/sys/cpu/byteorder.go
+++ b/libgo/go/golang.org/x/sys/cpu/byteorder.go
@@ -14,15 +14,20 @@
 func hostByteOrder() binary.ByteOrder {
 	switch runtime.GOARCH {
 	case "386", "amd64", "amd64p32",
+		"alpha",
 		"arm", "arm64",
 		"mipsle", "mips64le", "mips64p32le",
+		"nios2",
 		"ppc64le",
-		"riscv", "riscv64":
+		"riscv", "riscv64",
+		"sh":
 		return binary.LittleEndian
 	case "armbe", "arm64be",
+		"m68k",
 		"mips", "mips64", "mips64p32",
 		"ppc", "ppc64",
 		"s390", "s390x",
+		"shbe",
 		"sparc", "sparc64":
 		return binary.BigEndian
 	}