xmlconfig: fix scandir_filter

this was changed from a fnmatch usage to strcmp, and the return value
was flipped, breaking matching

also fix the formatting of the changed lines

Fixes: 4f37161a8f2: ("util/xmlconfig: Indent to Mesa style.")

Reviewed-by: Eric Anholt <eric@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7018>
diff --git a/src/util/xmlconfig.c b/src/util/xmlconfig.c
index b54fd10..6505fb4 100644
--- a/src/util/xmlconfig.c
+++ b/src/util/xmlconfig.c
@@ -947,9 +947,9 @@
       return 0;
 #endif
 
-    int len = strlen(ent->d_name);
-    if (len > 5 && strcmp(ent->d_name + len - 5, ".conf") == 0)
-       return 0;
+   int len = strlen(ent->d_name);
+   if (len <= 5 || strcmp(ent->d_name + len - 5, ".conf"))
+      return 0;
 
    return 1;
 }