Correct SPL uses of LMB

This converts 9 usages of this option to the non-SPL form, since there is
no SPL_LMB defined in Kconfig

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/m68k/lib/bootm.c b/arch/m68k/lib/bootm.c
index c1c9bdc..f18bed2 100644
--- a/arch/m68k/lib/bootm.c
+++ b/arch/m68k/lib/bootm.c
@@ -60,7 +60,7 @@
 	}
 	set_clocks_in_mhz(kbd);
 
-	if (CONFIG_IS_ENABLED(LMB)) {
+	if (IS_ENABLED(CONFIG_LMB)) {
 		ret = image_setup_linux(images);
 		if (ret)
 			goto error;