pch_can: fix tseg1/tseg2 setting issue

Previous patch "[PATCH 1/3] pch_can: fix 800k comms issue" is wrong.
I should have modified tseg1_min not tseg2_min.
This patch reverts tseg2_min to 1 and set tseg1_min to 2.

Signed-off-by: Tomoya MORINAGA <tomoya-linux@dsn.okisemi.com>
Signed-off-by: David S. Miller <davem@davemloft.net>