CAN: use hrtimers in can-bcm protocol

Make use of hrtimers to support high resolution capabilities, when
provided by the system clocksource.

The conversion to hrtimers additionally discovered and solved an
unlikely race condition that has been reproduced under (unrealistic)
massive receive load, which can only be produced on vcan software devices.

[ Fix printf format warnings on 64-bit -DaveM ]

Signed-off-by: Oliver Hartkopp <oliver@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>