km/ppc: use Kconfig for MEMTEST configuration

Also change back SYS_MEMTEST_END to 0x00f00000. 0xe00000 was wrong and
introduced due to the global Kconfig migration of this option in u-boot.

CC: Heiko Schocher <hs@denx.de>
CC: Tom Rini <trini@konsulko.com>
Signed-off-by: Holger Brunck <holger.brunck@hitachi-powergrids.com>
diff --git a/board/keymile/km83xx/Kconfig b/board/keymile/km83xx/Kconfig
index bbafabd..8247ae3 100644
--- a/board/keymile/km83xx/Kconfig
+++ b/board/keymile/km83xx/Kconfig
@@ -15,6 +15,12 @@
 	select PHYLIB
 endmenu
 
+config SYS_MEMTEST_START
+	default 0x00100000
+
+config SYS_MEMTEST_END
+	default 0x00f00000
+
 if TARGET_KMETER1
 
 config SYS_BOARD