i2c: Allow i2c_add_numbered_adapter() to assign a bus id

Currently, if an i2c bus driver supports both static and dynamic bus
ids, it needs to choose between calling i2c_add_numbered_adapter() and
i2c_add_adapter().  This patch makes i2c_add_numbered_adapter()
redirect to i2c_add_adapter() if the requested bus id is -1.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
diff --git a/drivers/i2c/busses/i2c-s6000.c b/drivers/i2c/busses/i2c-s6000.c
index cb5d01e..c64ba73 100644
--- a/drivers/i2c/busses/i2c-s6000.c
+++ b/drivers/i2c/busses/i2c-s6000.c
@@ -341,10 +341,7 @@
 	i2c_wr16(iface, S6_I2C_TXTL, 0);
 
 	platform_set_drvdata(dev, iface);
-	if (bus_num < 0)
-		rc = i2c_add_adapter(p_adap);
-	else
-		rc = i2c_add_numbered_adapter(p_adap);
+	rc = i2c_add_numbered_adapter(p_adap);
 	if (rc)
 		goto err_irq_free;
 	return 0;