mtd-utils.git: revert r24869 (convert to DOWNLOAD helper) to fix download

Reported by Thomas Petazzoni.

The git download doesn't work nicely with DOWNLOAD, so revert to the
direct WGET handling.

package/mtd/mtd-utils.git/mtd.mk

@@ -21,7 +21,7 @@ MKFS_JFFS2 := $(MTD_HOST_DIR)/mkfs.jffs2
 SUMTOOL := $(MTD_HOST_DIR)/sumtool
 
 $(DL_DIR)/$(MTD_SOURCE):
-	$(call DOWNLOAD,"$(MTD_URL)")
+	$(WGET) -O $(DL_DIR)/$(MTD_SOURCE) "$(MTD_URL)"
 
 $(MTD_HOST_DIR)/.unpacked: $(DL_DIR)/$(MTD_SOURCE)
 	$(MTD_CAT) $(DL_DIR)/$(MTD_SOURCE) | tar -C $(TOOL_BUILD_DIR) $(TAR_OPTIONS) -