hw/display/vmware_vga: skip automatic zero-init of large struct

hw/display/vmware_vga: skip automatic zero-init of large struct

The 'vmsvga_fifo_run' method has a struct which is a little over 20k
in size, used for holding image data for cursor changes. Skip the
automatic zero-init of this struct to eliminate the performance
overhead in the I/O hot path.

The cursor variable will be fully initialized only when processing
a cursor definition message from the guest.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20250610123709.835102-17-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>