can: bfin_can: simplify xmit id1 setup

If we look closely, the 4 writes to TRANSMIT_CHL.id1 can be collapsed
down into much simpler code.  So do just that.

This also fixes a build failure due to the I/O macros no longer
getting pulled in.  Their minor (and accidental) usage here gets
dropped as part of the unification.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be>
Signed-off-by: David S. Miller <davem@davemloft.net>