media: Kconfig: Better organize the per-API options

After this change, the menu is displayed like above.

1) When filtering is not active:

    --- Multimedia support
        [ ]   Filter devices by their types
        [*]   Autoselect ancillary drivers (tuners, sensors, i2c, spi, frontends)
              Media core support  --->
              Video4Linux options  --->
              Media controller options  --->
              Digital TV options  --->
              HDMI CEC options  --->
              Media drivers  --->

2) When filtering is active:

    --- Multimedia support
        [*]   Filter devices by their types
        [*]   Autoselect ancillary drivers (tuners, sensors, i2c, spi, frontends)
              Media device types  --->
              Video4Linux options  --->
              Media controller options  --->
              Digital TV options  --->
              HDMI CEC options  --->
              Media drivers  --->

The per-API menu will only be displayed if the corresponding
core support is enabled.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>