i2c: Move PPC4xx I2C driver into drivers/i2c directory

This patch moves the PPC4xx specific I2C device driver into the I2C
drivers directory. All 4xx config headers are updated to include this
driver.

Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/include/configs/CRAYL1.h b/include/configs/CRAYL1.h
index 96bf161..9ab30ec 100644
--- a/include/configs/CRAYL1.h
+++ b/include/configs/CRAYL1.h
@@ -65,6 +65,7 @@
  #define CONFIG_ETHADDR          00:40:a6:80:14:5
  */
 #define CONFIG_HARD_I2C         1		/* hardware support for i2c */
+#define CONFIG_PPC4XX_I2C		/* use PPC4xx driver		*/
 #define CONFIG_SDRAM_BANK0		1
 #define CONFIG_SYS_I2C_SPEED		    400000	/* I2C speed and slave address	*/
 #define CONFIG_SYS_I2C_SLAVE		    0x7F