media: platform: move some manufacturer entries

As there are 4 manufacturer's directories with multiple sources
(qcom, rockchip, sti and sunxi), move the sources from
platform/Kconfig to their specific Konfig files.

Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>