microblaze: Add partial decoding of stream insns

Based on a patch from: Alejandro Cabrera <aldaya@gmail.com>

Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
diff --git a/target-microblaze/microblaze-decode.h b/target-microblaze/microblaze-decode.h
index 4a27476..401319e 100644
--- a/target-microblaze/microblaze-decode.h
+++ b/target-microblaze/microblaze-decode.h
@@ -50,3 +50,6 @@
 #define DEC_BR      {B8(00100110), B8(00110111)}
 #define DEC_BCC     {B8(00100111), B8(00110111)}
 #define DEC_RTS     {B8(00101101), B8(00111111)}
+
+#define DEC_STREAM  {B8(00010011), B8(00110111)}
+