clk: renesas: rzg2l-cpg: Refactor Runtime PM clock validation

Refactor rzg2l_cpg_attach_dev to delegate clock validation for Runtime PM
to the updated rzg2l_cpg_is_pm_clk function. Ensure validation of clocks
associated with the power domain while excluding external and core clocks.
Prevent incorrect Runtime PM management for clocks outside the domain's
scope.

Update rzg2l_cpg_is_pm_clk to operate on a per-power-domain basis. Verify
clkspec.np against the domain's device node, check argument validity, and
validate clock type (CPG_MOD). Use the no_pm_mod_clks array to exclude
specific clocks from PM management.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/20241216210201.239855-1-prabhakar.mahadev-lad.rj@bp.renesas.com


Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>