i3c: master: Add basic driver for the Renesas I3C controller

Add a basic driver for the I3C controller found in Renesas RZ/G3S and
G3E SoCs. Support I3C pure busses (tested with two targets) and mixed
busses (two I3C devices plus various I2C targets). DAA and communication
with temperature sensors worked reliably at various speeds.

Missing features such as IBI, HotJoin, and target mode will be added
incrementally.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20250724094146.6443-5-wsa+renesas@sang-engineering.com


Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>