clk: meson: clean-up clock registration

Order, ids and size  between the table of regmap clocks and the onecell
data table could be different.

Set regmap pointer in all the regmap clocks before starting the
registration using the onecell data, to make sure we don't
get into an incoherent situation.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://lkml.kernel.org/r/20181221160239.26265-3-jbrunet@baylibre.com