winedos: Sign-compare warning fix

[Andrew Talbot]

Changelog:
    winedos: Sign-compare warning fix.

diff --git a/dlls/winedos/timer.c b/dlls/winedos/timer.c
index 74e41b5..0a504af 100644
--- a/dlls/winedos/timer.c
+++ b/dlls/winedos/timer.c
@@ -99,7 +99,7 @@ static void CALLBACK TIMER_TimerProc( HWND     hwnd,
     }
     else
     {
-        int i;
+        DWORD i;
 
         /* Calculate the number of valid timer interrupts we can generate */
         DWORD count = delta / TIMER_millis;