ice: dpll: Support E825-C SyncE and dynamic pin discovery

ice: dpll: Support E825-C SyncE and dynamic pin discovery

Implement SyncE support for the E825-C Ethernet controller using the
DPLL subsystem. Unlike E810, the E825-C architecture relies on platform
firmware (ACPI) to describe connections between the NIC's recovered clock
outputs and external DPLL inputs.

Implement the following mechanisms to support this architecture:

1. Discovery Mechanism: The driver parses the 'dpll-pins' and 'dpll-pin names'
   firmware properties to identify the external DPLL pins (parents)
   corresponding to its RCLK outputs ("rclk0", "rclk1"). It uses
   fwnode_dpll_pin_find() to locate these parent pins in the DPLL core.

2. Asynchronous Registration: Since the platform DPLL driver (e.g.
   zl3073x) may probe independently of the network driver, utilize
   the DPLL notifier chain The driver listens for DPLL_PIN_CREATED
   events to detect when the parent MUX pins become available, then
   registers its own Recovered Clock (RCLK) pins as children of those
   parents.

3. Hardware Configuration: Implement the specific register access logic
   for E825-C CGU (Clock Generation Unit) registers (R10, R11). This
   includes configuring the bypass MUXes and clock dividers required to
   drive SyncE signals.

4. Split Initialization: Refactor `ice_dpll_init()` to separate the
   static initialization path of E810 from the dynamic, firmware-driven
   path required for E825-C.

Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Co-developed-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Co-developed-by: Grzegorz Nitka <grzegorz.nitka@intel.com>
Signed-off-by: Grzegorz Nitka <grzegorz.nitka@intel.com>
Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
Link: https://patch.msgid.link/20260203174002.705176-10-ivecera@redhat.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>