i3c: Add comment for -EAGAIN in i3c_device_do_priv_xfers()

i3c: Add comment for -EAGAIN in i3c_device_do_priv_xfers()

In accordance with I3C spec ver 1.1.1 09-Jun-2021, section: 5.1.2.2.3, if
a target requests hot join (HJ), In-Band Interrupt (IBI), or controller
role request (CRR) during the emission of an I3C address in
i3c_device_do_priv_xfers(), the target may win bus arbitration. In such
cases, it is imperative to notify the I3C client driver and retry
i3c_device_do_priv_xfers() after some delay.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20240506164009.21375-1-Frank.Li@nxp.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>