y4minput.c: correct empty loop formatting

prefer {}s over ';'

Change-Id: I563fc82717e1deb4f42a40e03dca318c6adaa0c1
diff --git a/y4minput.c b/y4minput.c
index 34ea96d..2dbd603 100644
--- a/y4minput.c
+++ b/y4minput.c
@@ -61,11 +61,12 @@
   got_w = got_h = got_fps = got_interlace = got_par = got_chroma = 0;
   for (p = _tags;; p = q) {
     /*Skip any leading spaces.*/
-    while (*p == ' ')p++;
+    while (*p == ' ') p++;
     /*If that's all we have, stop.*/
-    if (p[0] == '\0')break;
+    if (p[0] == '\0') break;
     /*Find the end of this tag.*/
-    for (q = p + 1; *q != '\0' && *q != ' '; q++);
+    for (q = p + 1; *q != '\0' && *q != ' '; q++) {
+    }
     /*Process the tag.*/
     switch (p[0]) {
       case 'W': {