dt-bindings: i3c: Add adi-i3c-master

dt-bindings: i3c: Add adi-i3c-master

Add bindings doc for ADI I3C Controller IP core, a FPGA synthesizable IP
core that implements the MIPI I3C Basic controller specification.
The IP Core is versioned following Semantic Versioning 2.0.0 and
ADI's open-source HDL guidelines for devicetree bindings and drivers.

Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Jorge Marques <jorge.marques@analog.com>
Link: https://lore.kernel.org/r/20250827-adi-i3c-master-v9-1-04413925abe1@analog.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>