poweprc/km82xx: add board specific environment variable

On mgcoge3ne a new environment variable bobcatreset is used.
So this patch adds a possibility to add board specific
environment variables in general and this specific variable
for mgcoge3ne.

Signed-off-by: Holger Brunck <holger.brunck@keymile.com>
Acked-by: Heiko Schocher <hs@denx.de>
cc: Wolfgang Denk <wd@denx.de>
cc: Detlev Zundel <dzu@denx.de>
cc: Valentin Longchamp <valentin.longchamp@keymile.com>
Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>
diff --git a/include/configs/mgcoge3ne.h b/include/configs/mgcoge3ne.h
index f080619..7ed213e 100644
--- a/include/configs/mgcoge3ne.h
+++ b/include/configs/mgcoge3ne.h
@@ -85,6 +85,8 @@
 			PSDMR_WRC_2C				|\
 			PSDMR_CL_2)
 
+#define CONFIG_KM_BOARD_EXTRA_ENV	"bobcatreset=true\0"
+
 /* include further common stuff for all keymile 82xx boards */
 #include "km82xx-common.h"