soc: amlogic: clk-measure: add axg and g12a support

Add support for the axg and g12a SoC family in amlogic clk measure

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
[khilman: squashed some fixups from Martin]
Signed-off-by: Kevin Hilman <khilman@baylibre.com>