[WATCHDOG] s3c2410_wdt exit driver via labels

Cleanup the s3c2410_wdt driver's exit point by
using labels instead of multiple returns. Also
remove the checks for the resources having been
allocate in the exit, as we will now either have
fully allocated or not allocated the resources
at-all.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>