Remove unused mips workarounds.

This was never really finished, and hasn't been supported for years.

Test: treehugger
Change-Id: I21d4c3112aa8cf0c56e59f0cc19ff8725ef714b9

android/config.go

@@ -863,16 +863,7 @@ func (c *config) LibartImgHostBaseAddress() string {
 }
 
 func (c *config) LibartImgDeviceBaseAddress() string {
-	archType := Common
-	if len(c.Targets[Android]) > 0 {
-		archType = c.Targets[Android][0].Arch.ArchType
-	}
-	switch archType {
-	default:
-		return "0x70000000"
-	case Mips, Mips64:
-		return "0x5C000000"
-	}
+	return "0x70000000"
 }
 
 func (c *config) ArtUseReadBarrier() bool {