dpll: zl3073x: Implement phase offset monitor feature

dpll: zl3073x: Implement phase offset monitor feature

Implement phase offset monitor feature to allow a user to monitor
phase offsets across all available inputs.

The device firmware periodically performs phase offsets measurements for
all available DPLL channels and input references. The driver can ask
the firmware to fill appropriate latch registers with measured values.

There are 2 sets of latch registers for phase offsets reporting:

1) DPLL-to-connected-ref: up to 5 registers that contain values for
   phase offset between particular DPLL channel and its connected input
   reference.
2) selected-DPLL-to-ref: 10  registers that contain values for phase
   offsets between selected DPLL channel and all available input
   references.

Both are filled with single read request so the driver can read
DPLL-to-connected-ref phase offset for all DPLL channels at once.
This was implemented in the previous patch.

To read selected-DPLL-to-ref registers for all DPLLs a separate read
request has to be sent to device firmware for each DPLL channel.

To implement phase offset monitor feature:
* Extend zl3073x_ref_phase_offsets_update() to select given DPLL channel
  in phase offset read request. The caller can set channel==-1 if it
  will not read Type2 registers.
* Use this extended function to update phase offset latch registers
  during zl3073x_dpll_changes_check() call if phase monitor is enabled
* Extend zl3073x_dpll_pin_phase_offset_check() to check phase offset
  changes for all available input references
* Extend zl3073x_dpll_input_pin_phase_offset_get() to report phase
  offset values for all available input references
* Implement phase offset monitor callbacks to enable/disable this
  feature

Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Tested-by: Prathosh Satish <prathosh.satish@microchip.com>
Co-developed-by: Prathosh Satish <Prathosh.Satish@microchip.com>
Signed-off-by: Prathosh Satish <Prathosh.Satish@microchip.com>
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Link: https://patch.msgid.link/20250715144633.149156-4-ivecera@redhat.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>