ppc: Rework some hard-coded BOOTCOMMANDS

There are an assortment of hard-coded CONFIG_BOOTCOMMAND options in some
board headers.  Rework these so that they do not add to the CONFIG
namespace.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/include/configs/uniphier.h b/include/configs/uniphier.h
index 12028e5..a81fa9d 100644
--- a/include/configs/uniphier.h
+++ b/include/configs/uniphier.h
@@ -84,7 +84,7 @@
 #endif
 
 #define CONFIG_ROOTPATH			"/nfs/root/path"
-#define CONFIG_NFSBOOTCOMMAND						\
+#define NFSBOOTCOMMAND						\
 	"setenv bootargs $bootargs root=/dev/nfs rw "			\
 	"nfsroot=$serverip:$rootpath "					\
 	"ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname:$netdev:off;" \