km/common: add test sw starting variable

The test SW is started when the test_bank variable is set.

Signed-off-by: Thomas Herzmann <thomas.herzmann@keymile.com>
Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>
cc: Heiko Schocher <hs@denx.de>
cc: Wolfgang Denk <wd@denx.de>
Signed-off-by: Holger Brunck <holger.brunck@keymile.com>

include/configs/km/keymile-common.h

@@ -223,6 +223,8 @@
 	"backup_bank=0\0"						\
 	"release=run newenv; reset\0"					\
 	"pnvramsize=" xstr(CONFIG_KM_PNVRAM) "\0"			\
+	"testbootcmd=setenv boot_bank ${test_bank}; "			\
+		"run ${subbootcmds}; reset\0"				\
 	""
 
 #ifndef CONFIG_KM_DEF_ENV