Use the correct type for i when iterating over buf to avoid unlikely

negative array indexing in iicrdwr(..)

Differential Revision: https://reviews.freebsd.org/D5132
Obtained from: HardenedBSD
PR: 206754
Reported by: CTurt <cturt@hardenedbsd.org>
Submitted by: Madhi Moktari <mokhi64@gmail.com>
Sponsored by: EMC / Isilon Storage Division

sys/dev/iicbus/iic.c

@@ -293,7 +293,8 @@ iicrdwr(struct iic_cdevpriv *priv, struct iic_rdwr_data *d, int flags)
 	struct iic_msg *buf, *m;
 	void **usrbufs;
 	device_t iicdev, parent;
-	int error, i;
+	int error;
+	uint32_t i;
 
 	iicdev = priv->sc->sc_dev;
 	parent = device_get_parent(iicdev);