clk: amlogic: remove unnecessary headers

Some Amlogic clock controller drivers have a dedicated headers file, some
do not. Over time, these headers have evolved and now only carry register
offset definitions. These offsets are only used by the related controller
and are not meant to be shared.

These headers are not serving any purpose now.

Start enforcing some consistency between the different Amlogic clock
drivers and move the register offset definitions to the related driver.

Link: https://lore.kernel.org/r/20250623-clk-meson-no-headers-v1-1-468161a7279e@baylibre.com


[jbrunet: checkpatch strict: removed extra blank line]
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>