ppc4xx: Fix problem with I2C bus >= 1 initialization

This patch fixes a problem introduced with patch eb5eb2b0
[ppc4xx: Cleanup PPC4xx I2C infrastructure]. We need to assign the I2C
base address to the "i2c" pointer inside of the controller loop.
Otherwise controller 0 is initialized multiple times instead of
initializing each I2C controller sequentially.

Tested on Katmai.

Signed-off-by: Stefan Roese <sr@denx.de>
Acked-by: Heiko Schocher <hs@denx.de>
diff --git a/cpu/ppc4xx/i2c.c b/cpu/ppc4xx/i2c.c
index 7976e75..9b86187 100644
--- a/cpu/ppc4xx/i2c.c
+++ b/cpu/ppc4xx/i2c.c
@@ -93,7 +93,7 @@
 
 void i2c_init(int speed, int slaveaddr)
 {
-	struct ppc4xx_i2c *i2c = (struct ppc4xx_i2c *)I2C_BASE_ADDR;
+	struct ppc4xx_i2c *i2c;
 	int val, divisor;
 	int bus;
 
@@ -109,6 +109,9 @@
 	for (bus = 0; bus < CONFIG_SYS_MAX_I2C_BUS; bus++) {
 		I2C_SET_BUS(bus);
 
+		/* Set i2c pointer after calling I2C_SET_BUS() */
+		i2c = (struct ppc4xx_i2c *)I2C_BASE_ADDR;
+
 		/* Handle possible failed I2C state */
 		/* FIXME: put this into i2c_init_board()? */
 		_i2c_bus_reset();