can: xilinx_can: Limit CANFD brp to 2

Bit enlarging is observed for CANFD2.0 when brp is 1,
So change brp_min value to 2.

Signed-off-by: Srinivas Neeli <srinivas.neeli@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/bca871d7f3ca9c653d50e63c5b60028f2bdf3fb0.1600073396.git.michal.simek@xilinx.com


Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>