clk: meson: axg-audio: prepare sm1 addition

Rearrange the macro definition of the clocks of the axg-audio
controller. Also, the sm1 variant will feature tiny modification
of different blocks in this controller. Because of that, we need
to fallback to the old way of defining parent for some of the
clocks, using signal name.

Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>