i2c-ocores: Fix pointer type mismatch error

ocores_i2c_of_probe needs to use a const __be32 type for handing
device tree property values.  This patch fixed the following build
warning:

 CC      drivers/i2c/busses/i2c-ocores.o
  drivers/i2c/busses/i2c-ocores.c: In function 'ocores_i2c_of_probe':
  drivers/i2c/busses/i2c-ocores.c:254: warning: assignment discards qualifiers from pointer target type
  drivers/i2c/busses/i2c-ocores.c:261: warning: assignment discards qualifiers from pointer target type

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: linux-i2c@vger.kernel.org
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

drivers/i2c/busses/i2c-ocores.c

@@ -249,7 +249,7 @@ static struct i2c_adapter ocores_adapter = {
 static int ocores_i2c_of_probe(struct platform_device* pdev,
 				struct ocores_i2c* i2c)
 {
-	__be32* val;
+	const __be32* val;
 
 	val = of_get_property(pdev->dev.of_node, "regstep", NULL);
 	if (!val) {