ASoC: Support download of WM8958 MBC firmware

Allow userspace to supply an update to the ROM firmware. The firmware
request is non-blocking so userspace can load the firmware at its
leisure without delaying startup, the driver will begin using the
firmware the next time MBC is started after it has been supplied.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@ti.com>
diff --git a/sound/soc/codecs/wm8994.h b/sound/soc/codecs/wm8994.h
index 93a6cf1..1aa365b 100644
--- a/sound/soc/codecs/wm8994.h
+++ b/sound/soc/codecs/wm8994.h
@@ -10,6 +10,7 @@
 #define _WM8994_H
 
 #include <sound/soc.h>
+#include <linux/firmware.h>
 
 #include "wm_hubs.h"
 
@@ -114,6 +115,9 @@
 
 	unsigned int aif1clk_disable:1;
 	unsigned int aif2clk_disable:1;
+
+	const struct firmware *cur_fw;
+	const struct firmware *mbc;
 };
 
 #endif