Fix usermode virtual address type

Usermode virtual addresses are abi_ulong, not target_ulong.

Signed-off-by: Paul Brook <paul@codesourcery.com>
diff --git a/exec-all.h b/exec-all.h
index 6c44d32..56e7977 100644
--- a/exec-all.h
+++ b/exec-all.h
@@ -29,7 +29,7 @@
    addresses in userspace mode.  Define tb_page_addr_t to be an appropriate
    type.  */
 #if defined(CONFIG_USER_ONLY)
-typedef target_ulong tb_page_addr_t;
+typedef abi_ulong tb_page_addr_t;
 #else
 typedef ram_addr_t tb_page_addr_t;
 #endif