dpll: zl3073x: Add support to get/set esync on pins

Add support to get/set embedded sync for both input and output pins.
The DPLL is able to lock on input reference when the embedded sync
frequency is 1 PPS and pulse width 25%. The esync on outputs are more
versatille and theoretically supports any esync frequency that divides
current output frequency but for now support the same that supported on
input pins (1 PPS & 25% pulse).

Note that for the output pins the esync divisor shares the same register
used for N-divided signal formats. Due to this the esync cannot be
enabled on outputs configured with one of the N-divided signal formats.

Reviewed-by: Jiri Pirko <[email protected]>
Tested-by: Prathosh Satish <[email protected]>
Co-developed-by: Prathosh Satish <[email protected]>
Signed-off-by: Prathosh Satish <[email protected]>
Signed-off-by: Ivan Vecera <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Paolo Abeni <[email protected]>

Author: ivecera