arm/kirkwood: if CONFIG_SOFT_I2C is set don't set CONFIG_I2C_MVTWSI

Some boards e.g. keymile arm boards have CONFIG_CMD_I2C switched on
but they use soft i2c on kirkwood. So don't switch CONFIG_I2C_MVTWSI
on in this case.

Signed-off-by: Holger Brunck <holger.brunck@keymile.com>
cc: Valentin Longchamp <valentin.longchamp@keymile.com>
cc: Prafulla Wadaskar <prafulla@marvell.com>
cc: Heiko Schocher <hs@denx.de>

arch/arm/include/asm/arch-kirkwood/config.h

@@ -137,7 +137,9 @@
  * I2C related stuff
  */
 #ifdef CONFIG_CMD_I2C
+#ifndef CONFIG_SOFT_I2C
 #define CONFIG_I2C_MVTWSI
+#endif
 #define CONFIG_SYS_I2C_SLAVE		0x0
 #define CONFIG_SYS_I2C_SPEED		100000
 #endif