km/boards: fix typo for MAC address offset config option

This patch only fixes a typo.

Signed-off-by: Holger Brunck <holger.brunck@ch.abb.com>
CC: Stefan Roese <sr@denx.de>
CC: Valentin Longchamp <valentin.longchamp@ch.abb.com>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/board/keymile/Kconfig b/board/keymile/Kconfig
index 5f512d5..634dbbe 100644
--- a/board/keymile/Kconfig
+++ b/board/keymile/Kconfig
@@ -76,7 +76,7 @@
 	  Use the Ethernet initialization implemented in common code, which
 	  detects if a Piggy board is present.
 
-config PIGGY_MAC_ADRESS_OFFSET
+config PIGGY_MAC_ADDRESS_OFFSET
 	int "Piggy Address Offset"
 	default 0
 	help