net: ethernet: adi: adin1110: add PTP clock support

Add control for the PHC inside the ADIN1110/2111.
Device contains a syntonized counter driven by a 120 MHz
clock  with 8 ns resolution.

Time is stored on two registers: a 32bit seconds register and
a 32bit nanoseconds register.

For adjusting the clock timing, device uses an addend register.
Can generate an output signal on the TS_TIMER pin.
For reading the timestamp the current tiem is saved by setting the
TS_CAPT pin via gpio in order to snapshot both seconds and nanoseconds
in different registers that the live ones.

Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>