wineps.drv: Avoid signed-unsigned integer comparisons

[Andrew Talbot]

Changelog:
    wineps.drv: Avoid signed-unsigned integer comparisons.

diff --git a/dlls/wineps.drv/afm2c.c b/dlls/wineps.drv/afm2c.c
index 3f8b0ce..a0427e5 100644
--- a/dlls/wineps.drv/afm2c.c
+++ b/dlls/wineps.drv/afm2c.c
@@ -187,7 +187,7 @@ void PSDRV_AFM2C(const AFM *afm)
 {
     char    buffer[256];
     FILE    *of;
-    int     i;
+    unsigned int i;
 
     lstrcpynA(buffer, afm->FontName, sizeof(buffer) - 2);