i2c: ismt: initialize DMA buffer

This patch adds code to initialize the DMA buffer to compensate for
possible hardware data corruption.

Signed-off-by: James Ralston <james.d.ralston@intel.com>
[wsa: changed to use 'sizeof']
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
diff --git a/drivers/i2c/busses/i2c-ismt.c b/drivers/i2c/busses/i2c-ismt.c
index 8ed79a0..1672eff 100644
--- a/drivers/i2c/busses/i2c-ismt.c
+++ b/drivers/i2c/busses/i2c-ismt.c
@@ -393,6 +393,9 @@
 
 	desc = &priv->hw[priv->head];
 
+	/* Initialize the DMA buffer */
+	memset(priv->dma_buffer, 0, sizeof(priv->dma_buffer));
+
 	/* Initialize the descriptor */
 	memset(desc, 0, sizeof(struct ismt_desc));
 	desc->tgtaddr_rw = ISMT_DESC_ADDR_RW(addr, read_write);