i3c: master: fix Excess kernel-doc description warning

Remove the @boardinfo: line to prevent the kernel-doc warning:

include/linux/i3c/master.h:98: warning: Excess struct member 'boardinfo' description in 'i2c_dev_desc'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc:  <linux-i3c@lists.infradead.org>
Link: https://lore.kernel.org/r/20231223050542.13930-1-rdunlap@infradead.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>