tools/null_state_gen: Add macro to emit commands with null state

In null/golden context there are multiple state commands where
the actual state is always zero. For more compact batch representation
add a macro which just emits command and the rest of the state as zero.

v2: - Be more verbose about length bias (Bradley Volkin)
    - strip out unrelated state_offset declaration (Bradley Volkin)

Cc: Volkin, Bradley D <bradley.d.volkin@intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>

tools/null_state_gen/intel_batchbuffer.c

@@ -274,3 +274,18 @@ const char *intel_batch_type_as_str(const struct bb_item *item)
 
 	return "UNKNOWN";
 }
+
+void intel_batch_cmd_emit_null(struct intel_batchbuffer *batch,
+			       const int cmd, const int len, const int len_bias,
+			       const char *str)
+{
+	int i;
+
+	assert(len > 1);
+	assert((len - len_bias) >= 0);
+
+	bb_area_emit(batch->cmds, (cmd | (len - len_bias)), CMD, str);
+
+	for (i = len_bias-1; i < len; i++)
+		OUT_BATCH(0);
+}