media: stm32-dcmi: Drop unnecessary of_match_device() call

If probe is reached, we've already matched the device and in the case of
DT matching, the struct device_node pointer will be set. Therefore, there
is no need to call of_match_device() in probe.

Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>