include/ui/rect.h: fix qemu_rect_init() mis-assignment

include/ui/rect.h: fix qemu_rect_init() mis-assignment

Signed-off-by: Elen Avan <elen.avan@bk.ru>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2051
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2050
Fixes: a200d53b1fde "virtio-gpu: replace PIXMAN for region/rect test"
Cc: qemu-stable@nongnu.org
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>