i2c: i2c-pnx: Made buf type unsigned to prevent sign extension

Made buf type unsigned to prevent sign extension

Signed-off-by: Kevin Wells <kevin.wells@nxp.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
diff --git a/include/linux/i2c-pnx.h b/include/linux/i2c-pnx.h
index f13255e..9eb07bb 100644
--- a/include/linux/i2c-pnx.h
+++ b/include/linux/i2c-pnx.h
@@ -21,7 +21,7 @@
 	int			mode;		/* Interface mode */
 	struct completion	complete;	/* I/O completion */
 	struct timer_list	timer;		/* Timeout */
-	char *			buf;		/* Data buffer */
+	u8 *			buf;		/* Data buffer */
 	int			len;		/* Length of data buffer */
 };