ASoC imx-audmux: add MX31_AUDMUX_PORT7_SSI_PINS_7 define

The MX31 Audmux also has 7 Ports.
This patch adds the missing define, and makes the debugfs code iterate
over that port too.

Signed-off-by: Torben Hohn <torbenh@linutronix.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/sound/soc/fsl/imx-audmux.c b/sound/soc/fsl/imx-audmux.c
index 0803274..e7c800e 100644
--- a/sound/soc/fsl/imx-audmux.c
+++ b/sound/soc/fsl/imx-audmux.c
@@ -156,7 +156,7 @@
 		return;
 	}
 
-	for (i = 0; i < MX31_AUDMUX_PORT6_SSI_PINS_6 + 1; i++) {
+	for (i = 0; i < MX31_AUDMUX_PORT7_SSI_PINS_7 + 1; i++) {
 		snprintf(buf, sizeof(buf), "ssi%d", i);
 		if (!debugfs_create_file(buf, 0444, audmux_debugfs_root,
 					 (void *)i, &audmux_debugfs_fops))