vfio/pci: Fixup VFIOMSIXInfo comment

The fields were removed in the referenced commit, but the comment
still mentions them.

Fixes: 2fb9636e ("vfio-pci: Remove unused fields from VFIOMSIXInfo")
Tested-by: NAlexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: NEric Auger <eric.auger@redhat.com>
Tested-by: NEric Auger <eric.auger@redhat.com>
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>

hw/vfio/pci.h

@@ -86,7 +86,7 @@ enum {
     VFIO_INT_MSIX = 3,
 };
 
-/* Cache of MSI-X setup plus extra mmap and memory region for split BAR map */
+/* Cache of MSI-X setup */
 typedef struct VFIOMSIXInfo {
     uint8_t table_bar;
     uint8_t pba_bar;