media: platform: rename omap3isp/ to ti/omap3isp/

As the end goal is to have platform drivers split by vendor,
rename omap3isp/ to ti/omap3isp/.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>