media: MAINTAINERS: Orphan dw9768 and ov02a10 drivers

Dongchun's e-mail is no longer active and he hasn't given a new one:

	The following message to <dongchun.zhu@mediatek.com> was
	undeliverable.
	The reason for the problem:
	5.1.0 - Unknown address error 550-'Relaying mail to
	dongchun.zhu@mediatek.com is not allowed'

Mark the drivers as orphaned.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>