i2c.h: Provide a default CONFIG_SYS_I2C_SLAVE value

Many boards/controllers/drivers don't support an I2C slave interface,
however CONFIG_SYS_I2C_SLAVE is used in common code so provide a
default
Signed-off-by: NPeter Tyser <ptyser@xes-inc.com>

common/cmd_eeprom.c

@@ -401,10 +401,6 @@ eeprom_probe (unsigned dev_addr, unsigned offset)
 #define	CONFIG_SYS_I2C_SPEED	50000
 #endif
 
-#ifndef	CONFIG_SYS_I2C_SLAVE
-#define	CONFIG_SYS_I2C_SLAVE	0xFE
-#endif
-
 void eeprom_init  (void)
 {
 #if defined(CONFIG_SPI)

cpu/mpc8260/i2c.c

@@ -58,9 +58,6 @@ static unsigned int i2c_bus_num __attribute__ ((section (".data"))) = 0;
 #define	CONFIG_SYS_I2C_SPEED	50000
 #endif
 
-#ifndef	CONFIG_SYS_I2C_SLAVE
-#define	CONFIG_SYS_I2C_SLAVE	0xFE
-#endif
 /*-----------------------------------------------------------------------
  */
 

cpu/ppc4xx/40x_spd_sdram.c

@@ -56,10 +56,6 @@
 #define CONFIG_SYS_I2C_SPEED	50000
 #endif
 
-#ifndef CONFIG_SYS_I2C_SLAVE
-#define CONFIG_SYS_I2C_SLAVE	0xFE
-#endif
-
 #define ONE_BILLION	1000000000
 
 #define	 SDRAM0_CFG_DCE		0x80000000

cpu/ppc4xx/44x_spd_ddr.c

@@ -66,10 +66,6 @@
 #define CONFIG_SYS_I2C_SPEED	50000
 #endif
 
-#ifndef CONFIG_SYS_I2C_SLAVE
-#define CONFIG_SYS_I2C_SLAVE	0xFE
-#endif
-
 #define ONE_BILLION	1000000000
 
 /*

include/i2c.h

@@ -78,16 +78,22 @@
 #endif
 
 #ifdef CONFIG_8xx
-/* Set default values for the I2C bus speed and slave address on 8xx. In the
+/* Set default value for the I2C bus speed on 8xx. In the
  * future, we'll define these in all 8xx board config files.
  */
 #ifndef	CONFIG_SYS_I2C_SPEED
 #define	CONFIG_SYS_I2C_SPEED	50000
 #endif
+#endif
 
+/*
+ * Many boards/controllers/drivers don't support an I2C slave interface so
+ * provide a default slave address for them for use in common code.  A real
+ * value for CONFIG_SYS_I2C_SLAVE should be defined for any board which does
+ * support a slave interface.
+ */
 #ifndef	CONFIG_SYS_I2C_SLAVE
-#define	CONFIG_SYS_I2C_SLAVE	0xFE
-#endif
+#define	CONFIG_SYS_I2C_SLAVE	0xfe
 #endif
 
 /*