The CRC was stored in an unsigned variable in gem_receive. Change it for
a uint32_t to ensure we have the correct variable size here.

Signed-off-by: Luc Michel <luc.michel@amd.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by:  <sai.pavan.boddu@amd.com>
Message-id: 20231017194422.4124691-12-luc.michel@amd.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>