Silence some signedness warnings.

diff --git a/programs/winetest/gui.c b/programs/winetest/gui.c
index 67182aa..b1a5e48 100644
--- a/programs/winetest/gui.c
+++ b/programs/winetest/gui.c
@@ -515,8 +515,7 @@
         
     va_start (ap, t);
     if (t < sizeof text_funcs / sizeof text_funcs[0] &&
-        t < sizeof GUI_funcs / sizeof GUI_funcs[0] &&
-        t >= 0) ret = funcs[t](ap);
+        t < sizeof GUI_funcs / sizeof GUI_funcs[0]) ret = funcs[t](ap);
     else report (R_WARNING, "unimplemented report type: %d", t);
     va_end (ap);
     return ret;