clk: Add KUnit tests for clks registered with struct clk_parent_data

Test that clks registered with 'struct clk_parent_data' work as
intended and can find their parents.

Cc: Christian Marangi <ansuelsmth@gmail.com>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Reviewed-by: David Gow <davidgow@google.com>
Cc: Rae Moar <rmoar@google.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20240718210513.3801024-9-sboyd@kernel.org