virtio-gpu: fix potential divide-by-zero regression

Commit 9462ff4695aa0 ("virtio-gpu/win32: allocate shareable 2d
resources/images") introduces a division, which can lead to crashes when
"height" is 0.

Fixes: https://gitlab.com/qemu-project/qemu/-/issues/1744
Reviewed-by: Alexander Bulekov <alxndr@bu.edu>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
1 file changed