clk: meson: add sclk-ws driver

This is yet another simple but odd driver for the audio block of the g12a
and sm1 SoC families.

For TDMOUT's sclk to be properly inverted, bit 29 of
AUDIO_CLK_TDMOUT_x_CTRL should be the inverse of bit 28.
IOW bit28 == !bit29 at all times

This setting is automatically applied on axg and the manual setting was
added on g12a.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/20200729154359.1983085-2-jbrunet@baylibre.com

clk: meson: rework and clean drivers dependencies

Initially, the meson clock directory only hosted 2 controllers drivers,
for meson8 and gxbb. At the time, both used the same set of clock drivers
so managing the dependencies was not a big concern.

Since this ancient time, entropy did its job, controllers with different
requirement and specific clock drivers have been added. Unfortunately, we
did not do a great job at managing the dependencies between the
controllers and the different clock drivers. Some drivers, such as
clk-phase or vid-pll-div, are compiled even if they are useless on the
target (meson8). As we are adding new controllers, we need to be able to
pick a driver w/o pulling the whole thing.

The patch aims to clean things up by:
* providing a dedicated CONFIG_ for each clock drivers
* allowing clock drivers to be compiled as a modules, if possible
* stating explicitly which drivers are required by each controller.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://lkml.kernel.org/r/20190201125841.26785-5-jbrunet@baylibre.com