loader: warning fix

loadmod.c: In function ‘FreeSubdirs’:
loadmod.c:377: warning: passing argument 1 of ‘free’ discards qualifiers
from pointer target type
/usr/include/stdlib.h:488: note: expected ‘void *’ but argument is of
type ‘const char *’

Signed-off-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Daniel Stone <daniel@fooishbar.org>

hw/xfree86/loader/loadmod.c

@@ -374,7 +374,7 @@ FreeSubdirs(const char **subdirs)
 
     if (subdirs) {
 	for (s = subdirs; *s; s++)
-	    free(*s);
+	    free((char *)*s);
 	free(subdirs);
     }
 }