media: rzg2l-cru: Fix missing error code in rzg2l_cru_start_streaming_vq()

Failed to allocate scratch buffer, add the error code '-ENOMEM' to the
return value 'ret'.

drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c:676 rzg2l_cru_start_streaming_vq() warn: missing error code 'ret'.

Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=3275



Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>