clk: meson: meson8b: use a separate clock table for Meson8

The Meson8 SoC is slightly different compared to Meson8b and Meson8m2
because it does not have the glitch-free Mali GPU clock mux. For Meson8b
and Meson8m2 there are currently no known differences.

Add a separate clk_hw_onecell_data table for Meson8 so these differences
can be implemented. For now meson8_hw_onecell_data is a clone of our
existing meson8b_hw_onecell_data.
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://lkml.kernel.org/r/20181208171247.22238-3-martin.blumenstingl@googlemail.com