can: xilinx_can: remove repeated word from the kernel-doc

Trivial patch. Issue is reported by checkpatch.

Link: https://lore.kernel.org/all/267c11097c90debbb5b1efebbeabc98161177def.1632306843.git.michal.simek@xilinx.com


Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>