i3c: document i3c_xfers

i3c_xfers was left undocumented, document it.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Link: https://patch.msgid.link/20251202153804.2640623-2-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Author: alexandrebelloni

include/linux/i3c/master.h

@@ -418,7 +418,11 @@ struct i3c_bus {
  * @send_ccc_cmd: send a CCC command
  *		  This method is mandatory.
  * @priv_xfers: do one or several private I3C SDR transfers
- *		This method is mandatory.
+ *		This method is mandatory when i3c_xfers is not implemented. It
+ *		is deprecated.
+ * @i3c_xfers: do one or several I3C SDR or HDR transfers
+ *	       This method is mandatory when priv_xfers is not implemented but
+ *	       should be implemented instead of priv_xfers.
  * @attach_i2c_dev: called every time an I2C device is attached to the bus.
  *		    This is a good place to attach master controller specific
  *		    data to I2C devices.