Add msa mips features

References to an MSA architecture feature were added in
I3cadc29434dbd5fdb3aa780198414e90f9572ec5, but never added
to the build system.

Test: builds
Change-Id: I178813824a21475e013f7e8209d9473466ab821c

cc/config/mips64_device.go

@@ -97,7 +97,9 @@ func init() {
 	android.RegisterArchVariants(android.Mips64,
 		"mips64r2",
 		"mips64r6")
-	android.RegisterArchFeatures(android.Mips64, "rev6")
+	android.RegisterArchFeatures(android.Mips64,
+		"rev6",
+		"msa")
 	android.RegisterArchVariantFeatures(android.Mips64, "mips64r6",
 		"rev6")
 

cc/config/mips_device.go

@@ -135,7 +135,8 @@ func init() {
 		"mips32r6")
 	android.RegisterArchFeatures(android.Mips,
 		"dspr2",
-		"rev6")
+		"rev6",
+		"msa")
 	android.RegisterArchVariantFeatures(android.Mips, "mips32r2dspr2_fp",
 		"dspr2")
 	android.RegisterArchVariantFeatures(android.Mips, "mips32r6",