Correct SPL uses of SAVE_PREV_BL_FDT_ADDR

This converts 2 usages of this option to the non-SPL form, since there is
no SPL_SAVE_PREV_BL_FDT_ADDR defined in Kconfig

Signed-off-by: Simon Glass <sjg@chromium.org>

arch/arm/lib/save_prev_bl_data.c

@@ -60,7 +60,7 @@ int save_prev_bl_data(void)
 		return -ENODATA;
 	}
 
-	if (CONFIG_IS_ENABLED(SAVE_PREV_BL_FDT_ADDR))
+	if (IS_ENABLED(CONFIG_SAVE_PREV_BL_FDT_ADDR))
 		env_set_addr("prevbl_fdt_addr", (void *)reg0);
 	if (!CONFIG_IS_ENABLED(SAVE_PREV_BL_INITRAMFS_START_ADDR))
 		return 0;

common/board_r.c

@@ -453,7 +453,7 @@ static int initr_env(void)
 			    (unsigned long)map_to_sysmem(gd->fdt_blob));
 
 	#if (CONFIG_IS_ENABLED(SAVE_PREV_BL_INITRAMFS_START_ADDR) || \
-						CONFIG_IS_ENABLED(SAVE_PREV_BL_FDT_ADDR))
+						IS_ENABLED(CONFIG_SAVE_PREV_BL_FDT_ADDR))
 		save_prev_bl_data();
 	#endif