- Let clk_ops::init() return an error code
 - Add a clk_ops::terminate() callback to undo clk_ops::init()

* clk-init-allocation:
  clk: add terminate callback to clk_ops
  clk: let init callback return an error code
  clk: actually call the clock init before any other callback of the clock

* clk-unused:
  clk: bm1800: Remove set but not used variable 'fref'

* clk-register-dt-node-better:
  clk: Use parent node pointer during registration if necessary