dfu: minor: make debug output only verbose in info level

the longer output is to fast and often incomplete.
the shorter version is enough to view the progress when not
debugging.

Change-Id: I97bb84da68d1f3bc14fb7c05400edf1748f55460
diff --git a/firmware/apps/dfu/main.c b/firmware/apps/dfu/main.c
index 271fbec..97cd074 100644
--- a/firmware/apps/dfu/main.c
+++ b/firmware/apps/dfu/main.c
@@ -66,7 +66,11 @@
 		WDT_Restart(WDT);
 	}
 
-	printf("dnload(altif=%u, offset=%u, len=%u)\n\r", altif, offset, len);
+#if TRACE_LEVEL >= TRACE_LEVEL_INFO
+	TRACE_INFO("dnload(altif=%u, offset=%u, len=%u)\n\r", altif, offset, len);
+#else
+	printf("DL off=%u\n\r", offset);
+#endif
 
 #ifdef PINS_LEDS
 	PIO_Clear(&pinsLeds[LED_NUM_RED]);