i3c: Fix i3c_device_do_priv_xfers() kernel-doc indentation

i3c: Fix i3c_device_do_priv_xfers() kernel-doc indentation

Sphinx reports indentation warning on i3c_device_do_priv_xfers() return
value list:

Documentation/driver-api/i3c/device-driver-api:9: ./drivers/i3c/device.c:31: ERROR: Unexpected indentation. [docutils]

Format the list as bullet list to fix the warning.

Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20250702040424.18577-1-bagasdotme@gmail.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>