arm/km_kirkwood: remove KM_ENV_BUS and use CONFIG_I2C_ENV_EEPROM_BUS

KM_ENV_BUS was used for nothing else than an direct assignment to
CONFIG_I2C_ENV_EEPROM_BUS. To avoid this, directly use
CONFIG_I2C_ENV_EEPROM_BUS instead.

Patchwork: http://patchwork.ozlabs.org/patch/399411/
Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>

include/configs/km/km_arm.h

@@ -241,7 +241,7 @@ int get_scl(void);
 #define CONFIG_SYS_EEPROM_WREN
 #define CONFIG_ENV_OFFSET		0x0 /* no bracets! */
 #define CONFIG_ENV_SIZE			(0x2000 - CONFIG_ENV_OFFSET)
-#define CONFIG_I2C_ENV_EEPROM_BUS	KM_ENV_BUS
+#define CONFIG_I2C_ENV_EEPROM_BUS 5 /* I2C2 (Mux-Port 5) */
 #define CONFIG_ENV_OFFSET_REDUND	0x2000 /* no bracets! */
 #define CONFIG_ENV_SIZE_REDUND		(CONFIG_ENV_SIZE)
 #endif

include/configs/km_kirkwood.h

@@ -116,10 +116,6 @@
 /* include common defines/options for all arm based Keymile boards */
 #include "km/km_arm.h"
 
-#ifndef CONFIG_KM_ENV_IS_IN_SPI_NOR
-#define KM_ENV_BUS	5	/* I2C2 (Mux-Port 5)*/
-#endif
-
 #if defined(CONFIG_KM_PIGGY4_88E6352)
 /*
  * Some keymile boards like mgcoge5un & nusa1 have their PIGGY4 connected via