[media] staging: dt3155v4l: Switch to using managed resource with devm_

This patch uses managed resource APIs to allocate memory
in order to simplify the driver unload or failure cases

Signed-off-by: Kiran Padwal <kiran.padwal@smartplayin.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>