clk: renesas: Use pm_clk_no_clocks() helper i.s.o. direct access

The pm_subsys_data.clock_list member exists only if CONFIG_PM_CLK=y.
Hence direct accesses to this field break compile-testing on platforms
where CONFIG_PM_CLK=n.

To fix this, use the pm_clk_no_clocks() helper instead, for which a
dummy version is provided if CONFIG_PM_CLK=n.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Simon Horman <simon.horman@netronome.com>