mie: implement instruction selection graph generation for binary ops and load/store

mie/target/target.c

@@ -0,0 +1,13 @@
+#include <mie/target/target.h>
+
+const struct mie_target_select_ops __mie_builtin_select_ops;
+
+static const struct mie_target builtin_target = {
+	.t_name = "Mie",
+	.t_select = &__mie_builtin_select_ops,
+};
+
+const struct mie_target *mie_target_builtin(void)
+{
+	return &builtin_target;
+}