pci: reject too large ROMs

get_image_size() returns an int64_t, which pci_add_option_rom() assigns
to an "int" without any range checking.  A 32-bit BAR could be up to
2 GiB in size, so reject anything above it.  In order to accomodate
a rounded-up size of 2 GiB, change pci_patch_ids's size argument
to unsigned.

Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210203131828.156467-2-pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: David Edmondson <david.edmondson@oracle.com>