[PATCH] WAN/pc300: handle, propagate minor errors

- move definition of 'tmc' and 'br' locals closer to usage

- handle clock_rate_calc() error

- propagate errors back to upper level open routine

Signed-off-by: Jeff Garzik <jeff@garzik.org>
Cc: Krzysztof Halasa <khc@pm.waw.pl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>