spl: Make UBI fastmap support Kconfig selectable

Fastmap was always enabled in ubispl, make it selectable by
CONFIG_MTD_UBI_FASTMAP.

Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Acked-by: Heiko Schocher <hs@denx.de>
diff --git a/common/spl/spl_ubi.c b/common/spl/spl_ubi.c
index 24633f4..8308933 100644
--- a/common/spl/spl_ubi.c
+++ b/common/spl/spl_ubi.c
@@ -38,7 +38,7 @@
 		goto out;
 	}
 	info.ubi = (struct ubi_scan_info *)CONFIG_SPL_UBI_INFO_ADDR;
-	info.fastmap = 1;
+	info.fastmap = IS_ENABLED(CONFIG_MTD_UBI_FASTMAP);
 
 	info.peb_offset = CONFIG_SPL_UBI_PEB_OFFSET;
 	info.vid_offset = CONFIG_SPL_UBI_VID_OFFSET;