drm/i2c: tda998x: fix bad value in the AIF

The AIF has an uninitialized byte. This patch clears the whole buffer
before filling it.

Tested-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/drivers/gpu/drm/i2c/tda998x_drv.c b/drivers/gpu/drm/i2c/tda998x_drv.c
index 400b0c4..e620826 100644
--- a/drivers/gpu/drm/i2c/tda998x_drv.c
+++ b/drivers/gpu/drm/i2c/tda998x_drv.c
@@ -528,10 +528,10 @@
 {
 	uint8_t buf[PB(5) + 1];
 
+	memset(buf, 0, sizeof(buf));
 	buf[HB(0)] = 0x84;
 	buf[HB(1)] = 0x01;
 	buf[HB(2)] = 10;
-	buf[PB(0)] = 0;
 	buf[PB(1)] = p->audio_frame[1] & 0x07; /* CC */
 	buf[PB(2)] = p->audio_frame[2] & 0x1c; /* SF */
 	buf[PB(4)] = p->audio_frame[4];