Include back the 306ax microcode again.

In ee89435798 microcode for 306ax
was forgotten in migration.
Without microcode update my machine experiences random hangs and various
misbehaviour.

Change-Id: I61c704d88a8a0ed74a16fb3f80cce08e8515e6e2
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/10180
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>

src/cpu/intel/model_206ax/microcode_blob.c

@@ -19,4 +19,5 @@
 
 unsigned microcode[] = {
 	#include "../../../../3rdparty/blobs/cpu/intel/model_206ax/microcode.h"
+	#include "../../../../3rdparty/blobs/cpu/intel/model_306ax/microcode.h"
 };