media: platform: move platform menu dependencies to drivers

Right now, platform dependencies are organized by the type of
the platform driver. Yet, things tend to become very messy with
time. The better seems to organize the drivers per manufacturer,
as other Kernel subsystems are doing.

As a preparation for such purpose, get rid of menuconfigs,
moving the per-menu dependencies to be at the driver-specifig
config entires.

This shoud give flexibility to reorganize the platform drivers
per manufacturer and re-sort them.

This patch removes all "if..endif" options from the platform
Kconfig, converting them into depends on.

Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>