tests/modetest: use drmGetFormatName()

Signed-off-by: Simon Ser <contact@emersion.fr>
Reviewed-by: Marius Vlad <marius.vlad@collabora.com>
Reviewed-by: Eric Engestrom <eric@igalia.com>

tests/modetest/modetest.c

@@ -187,11 +187,9 @@ static bit_name_fn(mode_flag)
 
 static void dump_fourcc(uint32_t fourcc)
 {
-	printf(" %c%c%c%c",
-		fourcc,
-		fourcc >> 8,
-		fourcc >> 16,
-		fourcc >> 24);
+	char *name = drmGetFormatName(fourcc);
+	printf(" %s", name);
+	free(name);
 }
 
 static void dump_encoders(struct device *dev)