media: platform: re-structure TI drivers

The ti-vpe/ sub-directory does not only contain the VPE-specific things.
It also contains the CAL driver, which is a completely different
subsystem. This is also not a good place to add new drivers for other TI
platforms since they will all get mixed up.

Separate the VPE and CAL parts into different sub-directories and rename
the ti-vpe/ sub-directory to ti/. This is now the place where new TI
platform drivers can be added.

[mchehab: rebased to apple on the top of media/platform/Kconfig series]
Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>