qemu: msix nit: clear msix_entries_nr on error

I don't think it's critical to do this, but it's
best to keep uninit and error recovery consistent.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

hw/msix.c

diff --git a/hw/msix.c b/hw/msix.c
index 3420ce9..c954d47 100644
--- a/hw/msix.c
+++ b/hw/msix.c
@@ -255,6 +255,7 @@
     return 0;
 
 err_config:
+    dev->msix_entries_nr = 0;
     cpu_unregister_io_memory(dev->msix_mmio_index);
 err_index:
     qemu_free(dev->msix_table_page);