media: ti-vpe: Simplify bool comparison

Fix the following coccicheck warning:

./drivers/media/platform/ti-vpe/vpdma.c:946:5-26: WARNING: Comparison to
bool.

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+huawei@kernel.org>