arm/km: remove CONFIG_SYS_KWD_CONFIG from keymile-common.h

This define is marvell specific, so it should be present in km_arm.
It is however not needed there either, since we set it to the default
value that is already set in include/asm/arch-kirkwood/config.h

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

include/configs/km/keymile-common.h

@@ -30,15 +30,6 @@
 
 #define CONFIG_BOOTCOUNT_LIMIT
 
-/*
- * By default kwbimage.cfg from board specific folder is used
- * If for some board, different configuration file need to be used,
- * CONFIG_SYS_KWD_CONFIG should be defined in board specific header file
- */
-#ifndef CONFIG_SYS_KWD_CONFIG
-#define	CONFIG_SYS_KWD_CONFIG	$(SRCTREE)/$(CONFIG_BOARDDIR)/kwbimage.cfg
-#endif /* CONFIG_SYS_KWD_CONFIG */
-
 /*
  * Command line configuration.
  */