Fix crash with kvm enabled.

Signed-off-by: Stefan Weil <weil@mail.berlios.de> 

Index: target-i386/kvm.c
===================================================================
--- target-i386/kvm.c	(revision 5889)
+++ target-i386/kvm.c	(working copy)
@@ -39,7 +39,7 @@
         struct kvm_cpuid cpuid;
         struct kvm_cpuid_entry entries[100];
     } __attribute__((packed)) cpuid_data;
-    int limit, i, cpuid_i;
+    uint32_t limit, i, cpuid_i;
     uint32_t eax, ebx, ecx, edx;
 
     cpuid_i = 0;